diff --git a/src/components/main/StudyGroups.jsx b/src/components/main/StudyGroups.jsx
index 53eb1d1..1017b0e 100644
--- a/src/components/main/StudyGroups.jsx
+++ b/src/components/main/StudyGroups.jsx
@@ -1,7 +1,11 @@
 import React from 'react';
 
+import { Link } from 'react-router-dom';
+
 import styled from '@emotion/styled';
 
+import palette from '../../styles/palette';
+
 import StudyGroup from './StudyGroup';
 
 const StudyGroupsWrapper = styled.div`
@@ -11,16 +15,44 @@ const StudyGroupsWrapper = styled.div`
   align-content: space-between;
 `;
 
-const StudyGroups = ({ groups, realTime }) => (
-  <StudyGroupsWrapper>
-    {groups.map((group) => (
-      <StudyGroup
-        key={group.id}
-        group={group}
-        realTime={realTime}
-      />
-    ))}
-  </StudyGroupsWrapper>
+const TitleHeader = styled.div`
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  // TODO: Link 공통 style component 만들기
+  a {
+    margin-right: 4rem;
+    padding: .6rem .9rem .6rem .9rem;
+    border: 1px solid ${palette.gray[7]};
+    background: white;
+    color: ${palette.gray[7]};
+    font-weight: bold;
+    border-radius: .7rem;
+    :hover {
+      color: white;
+      background: ${palette.gray[7]};
+    }
+  }
+`;
+
+const StudyGroups = ({ groups, realTime, user }) => (
+  <>
+    <TitleHeader>
+      <h2>지금 바로 시작하세요!</h2>
+      {user && (
+        <Link to="/write">스터디 개설하기</Link>
+      )}
+    </TitleHeader>
+    <StudyGroupsWrapper>
+      {groups.map((group) => (
+        <StudyGroup
+          key={group.id}
+          group={group}
+          realTime={realTime}
+        />
+      ))}
+    </StudyGroupsWrapper>
+  </>
 );
 
 export default StudyGroups;
diff --git a/src/containers/groups/StudyGroupsContainer.jsx b/src/containers/groups/StudyGroupsContainer.jsx
index b0ab91a..2016417 100644
--- a/src/containers/groups/StudyGroupsContainer.jsx
+++ b/src/containers/groups/StudyGroupsContainer.jsx
@@ -18,6 +18,7 @@ const StudyGroupsContainer = () => {
   const dispatch = useDispatch();
 
   const groups = useSelector(get('groups'));
+  const user = useSelector(get('user'));
 
   useInterval(() => {
     setRealTime(Date.now());
@@ -37,6 +38,7 @@ const StudyGroupsContainer = () => {
 
   return (
     <StudyGroups
+      user={user}
       groups={groups}
       realTime={realTime}
     />
diff --git a/src/containers/write/WriteButtonsContainer.jsx b/src/containers/write/WriteButtonsContainer.jsx
index c8864d7..f0feef2 100644
--- a/src/containers/write/WriteButtonsContainer.jsx
+++ b/src/containers/write/WriteButtonsContainer.jsx
@@ -11,7 +11,9 @@ import WriteButtons from '../../components/write/WriteButtons';
 
 const isCheckApplyEndDate = (applyDate) => Date.now() - applyDate >= 0;
 
-const { NO_INPUT, NO_TAG, FAST_APPLY_DEADLINE } = ERROR_MESSAGE;
+const {
+  NO_INPUT, NO_TAG, FAST_APPLY_DEADLINE, NO_LOGGED_IN,
+} = ERROR_MESSAGE;
 
 const WriteButtonsContainer = () => {
   const [error, setError] = useState(null);
@@ -21,6 +23,7 @@ const WriteButtonsContainer = () => {
 
   const writeField = useSelector(get('writeField'));
   const groupId = useSelector(get('groupId'));
+  const user = useSelector(get('user'));
 
   const {
     title, applyEndDate, personnel, tags,
@@ -29,6 +32,12 @@ const WriteButtonsContainer = () => {
   const applyEndTime = new Date(applyEndDate).getTime();
 
   const onSubmit = () => {
+    // TODO: 모달창으로 처리 후 redirection 시키기?
+    if (!user) {
+      setError(NO_LOGGED_IN);
+      return;
+    }
+
     if (isCheckValidate([title, applyEndDate, personnel])) {
       setError(NO_INPUT);
       return;
diff --git a/src/containers/write/WriteButtonsContainer.test.jsx b/src/containers/write/WriteButtonsContainer.test.jsx
index 7db70e6..3b1bb1a 100644
--- a/src/containers/write/WriteButtonsContainer.test.jsx
+++ b/src/containers/write/WriteButtonsContainer.test.jsx
@@ -30,6 +30,7 @@ describe('WriteButtonsContainer', () => {
     useSelector.mockImplementation((state) => state({
       writeField: given.writeField,
       groupId: given.groupId,
+      user: given.user,
     }));
   });
 
@@ -62,101 +63,131 @@ describe('WriteButtonsContainer', () => {
   });
 
   describe('when click submit button', () => {
-    context('without input value null, so validation check success', () => {
-      given('writeField', () => (WRITE_FORM));
+    context('with user', () => {
+      given('user', () => ('user'));
 
-      context('with group', () => {
-        given('groupId', () => ('1'));
+      context('without input value null, so validation check success', () => {
+        given('writeField', () => (WRITE_FORM));
 
-        it('dispatch action writeStudyGroup event', () => {
-          const { getByText } = renderWriteButtonsContainer();
+        context('with group', () => {
+          given('groupId', () => ('1'));
 
-          fireEvent.click(getByText('등록하기'));
+          it('dispatch action writeStudyGroup event', () => {
+            const { getByText } = renderWriteButtonsContainer();
 
-          expect(dispatch).toBeCalledTimes(1);
+            fireEvent.click(getByText('등록하기'));
 
-          expect(mockPush).toBeCalledWith('/introduce/1');
+            expect(dispatch).toBeCalledTimes(1);
+
+            expect(mockPush).toBeCalledWith('/introduce/1');
+          });
         });
-      });
 
-      context('without group', () => {
-        given('groupId', () => (null));
+        context('without group', () => {
+          given('groupId', () => (null));
 
-        it('dispatch action submit event', () => {
-          const { getByText } = renderWriteButtonsContainer();
+          it('dispatch action submit event', () => {
+            const { getByText } = renderWriteButtonsContainer();
 
-          fireEvent.click(getByText('등록하기'));
+            fireEvent.click(getByText('등록하기'));
 
-          expect(mockPush).not.toBeCalled();
+            expect(mockPush).not.toBeCalled();
+          });
         });
       });
-    });
-    context('with input value null, so validation check failure', () => {
-      describe('When the title and applyEndDate, personnel are blank', () => {
-        given('writeField', () => ({
-          title: '',
-          contents: '우리는 이것저것 합니다.1',
-          moderatorId: 'user1',
-          applyEndDate: '',
-          participants: [],
-          personnel: '',
-          tags: [
-            'JavaScript',
-            'Algorithm',
-          ],
-        }));
-
-        it('renders error message "There are some items that have not been entered."', () => {
-          const { container, getByText } = renderWriteButtonsContainer();
-
-          fireEvent.click(getByText('등록하기'));
-
-          expect(container).toHaveTextContent('입력이 안된 사항이 있습니다.');
+
+      context('with input value null, so validation check failure', () => {
+        describe('When the title and applyEndDate, personnel are blank', () => {
+          given('writeField', () => ({
+            title: '',
+            contents: '우리는 이것저것 합니다.1',
+            moderatorId: 'user1',
+            applyEndDate: '',
+            participants: [],
+            personnel: '',
+            tags: [
+              'JavaScript',
+              'Algorithm',
+            ],
+          }));
+
+          it('renders error message "There are some items that have not been entered."', () => {
+            const { container, getByText } = renderWriteButtonsContainer();
+
+            fireEvent.click(getByText('등록하기'));
+
+            expect(container).toHaveTextContent('입력이 안된 사항이 있습니다.');
+          });
         });
-      });
 
-      describe('When the length of tags is 0', () => {
-        given('writeField', () => ({
-          title: '123',
-          contents: '우리는 이것저것 합니다.1',
-          moderatorId: 'user1',
-          applyEndDate: new Date().toString(),
-          participants: [],
-          personnel: '1',
-          tags: [],
-        }));
+        describe('When the length of tags is 0', () => {
+          given('writeField', () => ({
+            title: '123',
+            contents: '우리는 이것저것 합니다.1',
+            moderatorId: 'user1',
+            applyEndDate: new Date().toString(),
+            participants: [],
+            personnel: '1',
+            tags: [],
+          }));
 
-        it('renders error message "Please enter a tag."', () => {
-          const { container, getByText } = renderWriteButtonsContainer();
+          it('renders error message "Please enter a tag."', () => {
+            const { container, getByText } = renderWriteButtonsContainer();
 
-          fireEvent.click(getByText('등록하기'));
+            fireEvent.click(getByText('등록하기'));
 
-          expect(container).toHaveTextContent('태그를 입력하세요.');
+            expect(container).toHaveTextContent('태그를 입력하세요.');
+          });
         });
-      });
 
-      describe('When the application deadline is earlier than the current time', () => {
-        given('writeField', () => ({
-          title: '123',
-          contents: '우리는 이것저것 합니다.1',
-          moderatorId: 'user1',
-          applyEndDate: '2020-10-01',
-          participants: [],
-          personnel: '1',
-          tags: [
-            'javascript',
-            'react',
-          ],
-        }));
-
-        it('renders error message "The application deadline is earlier than the current time."', () => {
-          const { container, getByText } = renderWriteButtonsContainer();
-
-          fireEvent.click(getByText('등록하기'));
-
-          expect(container).toHaveTextContent('접수 마감날짜가 현재 시간보다 빠릅니다.');
+        describe('When the application deadline is earlier than the current time', () => {
+          given('writeField', () => ({
+            title: '123',
+            contents: '우리는 이것저것 합니다.1',
+            moderatorId: 'user1',
+            applyEndDate: '2020-10-01',
+            participants: [],
+            personnel: '1',
+            tags: [
+              'javascript',
+              'react',
+            ],
+          }));
+
+          it('renders error message "The application deadline is earlier than the current time."', () => {
+            const { container, getByText } = renderWriteButtonsContainer();
+
+            fireEvent.click(getByText('등록하기'));
+
+            expect(container).toHaveTextContent('접수 마감날짜가 현재 시간보다 빠릅니다.');
+          });
         });
       });
     });
+
+    context('without user', () => {
+      given('user', () => (null));
+
+      given('writeField', () => ({
+        title: '123',
+        contents: '우리는 이것저것 합니다.1',
+        moderatorId: 'user1',
+        applyEndDate: '2020-10-01',
+        participants: [],
+        personnel: '1',
+        tags: [
+          'javascript',
+          'react',
+        ],
+      }));
+
+      it('renders error message "Please use after logging in"', () => {
+        const { container, getByText } = renderWriteButtonsContainer();
+
+        fireEvent.click(getByText('등록하기'));
+
+        expect(container).toHaveTextContent('로그인 후 이용하세요.');
+      });
+    });
   });
 });
diff --git a/src/pages/MainPage.jsx b/src/pages/MainPage.jsx
index 3eaddee..8fa08b8 100644
--- a/src/pages/MainPage.jsx
+++ b/src/pages/MainPage.jsx
@@ -1,45 +1,13 @@
 import React from 'react';
 
-import { Link } from 'react-router-dom';
-
-import styled from '@emotion/styled';
-
-import StudyGroupsContainer from '../containers/groups/StudyGroupsContainer';
 import Responsive from '../styles/Responsive';
-import palette from '../styles/palette';
 
-const MainPageWrapper = styled(Responsive)`
-
-`;
-
-const TitleHeader = styled.div`
-  display: flex;
-  justify-content: space-between;
-  align-items: center;
-  // TODO: Link 공통 style component 만들기
-  a {
-    margin-right: 4rem;
-    padding: .6rem .9rem .6rem .9rem;
-    border: 1px solid ${palette.gray[7]};
-    background: white;
-    color: ${palette.gray[7]};
-    font-weight: bold;
-    border-radius: .7rem;
-    :hover {
-      color: white;
-      background: ${palette.gray[7]};
-    }
-  }
-`;
+import StudyGroupsContainer from '../containers/groups/StudyGroupsContainer';
 
 const MainPage = () => (
-  <MainPageWrapper>
-    <TitleHeader>
-      <h2>지금 바로 시작하세요!</h2>
-      <Link to="/write">스터디 개설하기</Link>
-    </TitleHeader>
+  <Responsive>
     <StudyGroupsContainer />
-  </MainPageWrapper>
+  </Responsive>
 );
 
 export default MainPage;
diff --git a/src/pages/MainPage.test.jsx b/src/pages/MainPage.test.jsx
index d647d86..0c1c9e1 100644
--- a/src/pages/MainPage.test.jsx
+++ b/src/pages/MainPage.test.jsx
@@ -19,6 +19,7 @@ describe('MainPage', () => {
 
     useSelector.mockImplementation((selector) => selector({
       groups: STUDY_GROUPS,
+      user: given.user,
     }));
   });
 
@@ -35,12 +36,6 @@ describe('MainPage', () => {
       expect(container).toHaveTextContent('지금 바로 시작하세요!');
     });
 
-    it('renders Main Page Link text', () => {
-      const { container } = renderMainPage();
-
-      expect(container).toHaveTextContent('스터디 개설하기');
-    });
-
     it('renders Main Page study group tags', () => {
       const { container } = renderMainPage();
 
@@ -50,6 +45,24 @@ describe('MainPage', () => {
         });
       });
     });
+
+    context('without user', () => {
+      given('user', () => (null));
+      it("doesn't renders Main Page Link text", () => {
+        const { container } = renderMainPage();
+
+        expect(container).not.toHaveTextContent('스터디 개설하기');
+      });
+    });
+
+    context('with user', () => {
+      given('user', () => ('user'));
+      it('renders Main Page Link text', () => {
+        const { container } = renderMainPage();
+
+        expect(container).toHaveTextContent('스터디 개설하기');
+      });
+    });
   });
 
   it('calls dispatch with loadStudyGroups action', () => {
diff --git a/src/reducers/slice.js b/src/reducers/slice.js
index 4eada5f..68e6154 100644
--- a/src/reducers/slice.js
+++ b/src/reducers/slice.js
@@ -184,14 +184,12 @@ export const loadStudyGroup = (id) => async (dispatch) => {
 };
 
 export const writeStudyGroup = () => async (dispatch, getState) => {
-  const { writeField } = getState();
+  const { writeField, user } = getState();
 
-  // NOTE: 현재 로그인 기능이 없는 관계로 임의로 작성자(moderatorId)와 참여자 목록(participants)에 넣어줌
-  const groupId = await postStudyGroup({
-    ...writeField,
-    moderatorId: 'user1',
-    participants: [...writeField.participants, 'user1'],
-  });
+  const groupId = await postStudyGroup(produce(writeField, (draft) => {
+    draft.moderatorId = user;
+    draft.participants.push(user);
+  }));
 
   dispatch(successWrite(groupId));
   dispatch(clearWriteFields());
@@ -204,7 +202,6 @@ export const updateStudyGroup = () => async (dispatch, getState) => {
     draft.participants.push(user);
   });
 
-  // TODO: 같은 유저가 들어가도 update 된다. validation 하기
   await updateParticipants(newGroup);
 
   dispatch(setStudyGroup(newGroup));
diff --git a/src/util/messages.js b/src/util/messages.js
index d6e6eb0..cf5f7f6 100644
--- a/src/util/messages.js
+++ b/src/util/messages.js
@@ -5,6 +5,7 @@ export const ERROR_MESSAGE = {
   FAST_APPLY_DEADLINE: '접수 마감날짜가 현재 시간보다 빠릅니다.',
   FAILURE_REGISTER: '회원가입에 실패하였습니다.',
   FAILURE_LOGIN: '로그인에 실패하였습니다.',
+  NO_LOGGED_IN: '로그인 후 이용하세요.',
 };
 
 export const FIREBASE_AUTH_ERROR_MESSAGE = {