ガイド · 更新日 2026年11月3日

How to clear cookies on a Mac in Safari, Chrome and Firefox

How to delete all cookies, or just one site's, in each browser on a Mac, what you lose when you do, and when clearing them actually fixes something.

macOS 26 Tahoe 以降 · クレジットカード不要 · すべて Mac 上で実行

The short answer: in Safari, choose Safari › Settings › Privacy › Manage Website Data, then Remove All. In Chrome, press ⇧ ⌘ Delete, tick Cookies and other site data and click Delete data. In Firefox, open Settings › Privacy & Security › Cookies and Site Data › Clear Data. Clearing cookies signs you out of websites, so if only one site misbehaves, remove that site's cookies alone.

Clear cookies in Safari

  1. Choose Safari › Settings and click Privacy.
  2. Click Manage Website Data. The list shows every site that has stored cookies or other data on your Mac.
  3. To clear one site, type its name in the search field, select it and click Remove. To clear everything, click Remove All.

History › Clear History removes cookies too, along with your history and cache, for the time range you choose. Use it when you want to clear everything from, say, the last hour.

Clear cookies in Chrome

  1. Press ⇧ ⌘ Delete, or open Settings › Privacy and security › Delete browsing data.
  2. Choose a time range; All time clears every cookie.
  3. Tick Cookies and other site data, untick what you want to keep, and click Delete data.

For one site, open it, click the icon to the left of the address, and choose Cookies and site data › Manage on-device site data, then delete the entries. Edge, Brave and other Chromium browsers work the same way. If you are signed in to Chrome, clearing cookies doesn't sign you out of your Google Account in Chrome itself.

Clear cookies in Firefox

  1. Open Settings › Privacy & Security and scroll to Cookies and Site Data.
  2. Click Clear Data, tick cookies and site data, and click Clear.
  3. For one site, click Manage Data instead, search for it, and click Remove Selected.

What happens when you clear cookies

  • You are signed out of websites, and some ask you to confirm your identity again with a code.
  • Shopping carts, site preferences such as language or dark mode, and cookie banners you already answered are reset.
  • Your saved passwords, bookmarks and history stay, unless you tick them too. Passwords are kept separately, in the Passwords app or the browser's password manager.
  • Advertising and tracking cookies are gone, until the next site you visit sets new ones.

When clearing cookies helps

  • A site keeps sending you back to the sign-in page, shows an error after you sign in, or displays the wrong account: clear that site's cookies only.
  • You used a shared or borrowed Mac and want to be signed out everywhere.
  • You want to reset what sites and ad networks remember about you.

Clearing cookies doesn't speed up a Mac or free meaningful disk space; they take up very little. For space, clear the cache instead: see how to clear cache on a Mac.

Fewer tracking cookies without clearing them

  • Safari blocks cross-site tracking by default; check that Prevent cross-site tracking is on under Safari › Settings › Privacy.
  • A private window keeps no cookies after you close it, which is handy for a one-off visit or a second account.
  • Blocking tracker servers stops many tracking cookies being set in the first place, in every browser; see ad blockers for Mac.

Clear cookies in every browser with Tidy My Mac

  • Privacy Cleanup clears cookies, history and caches in Safari, Chrome, Edge, Brave, Arc, Vivaldi and Firefox, profile by profile, from one list. It never touches saved passwords, and Put Back restores what it cleared.
  • Web Protection blocks ad and tracker servers in every browser and app, so fewer tracking cookies are set.
  • Browser Extensions shows which extensions can read your cookies on every site.

Clearing cookiesに関するよくある質問

Not as routine maintenance: it signs you out everywhere and saves little space. Clear one site's cookies when that site misbehaves, and all of them after using a shared Mac or if you want to reset tracking.

No. Saved passwords are stored separately and stay. You are signed out of sites, so you may need those passwords, and any two-factor codes, to sign in again.

In Safari, use Manage Website Data in the Privacy settings and remove that site. In Chrome, click the icon left of the address and manage the site's data. In Firefox, use Manage Data under Cookies and Site Data.

The cache keeps copies of pages and images so sites load faster; clearing it frees space and keeps you signed in. Cookies hold your sign-ins and preferences; clearing them signs you out but frees almost no space.

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