PDFメタデータ編集 – 無料オンライン

Edit PDF metadata — change title, author, subject, keywords online

PDF metadata controls what appears in document properties, search results, and file manager previews. This tool lets you view and edit the title, author, subject, keywords, and creator fields of any PDF. All editing happens in your browser — your file is never uploaded.

Why edit PDF metadata?

• SEO for PDFs — search engines index PDF metadata. A good title and keywords help your PDF rank.
• Professionalism — sending a PDF with "Microsoft Word - Document1" as the title looks unprofessional.
• Organization — proper metadata makes PDFs easier to find in file managers and document management systems.
• Privacy — remove author and creator info that reveals your name, computer name, or software version.

Supported fields

• Title — displayed in browser tabs and PDF reader title bars.
• Author — the document's author name.
• Subject — a brief description of the document's topic.
• Keywords — searchable tags, separated by commas or spaces.
• Creator — the application that originally created the PDF.

What's inside PDF metadata

Every PDF carries a metadata block with the document title, author, subject, keywords, creator (the application that produced it), and producer (the PDF library that wrote it). Search engines, document management systems (DMS), and library indexers all read this metadata. Stale or wrong metadata makes your file harder to find — and embedded usernames or laptop names can quietly leak who actually wrote a "company" document.

What you can edit

• Title — replaces the filename in many readers' window titles and in DMS search results.
• Author — useful when handing a document off, or when the original author is a personal username that shouldn't be in the public file.
• Subject — one-line topical description, used by enterprise search.
• Keywords — comma-separated index terms, surfaced by document management systems.
• Creation and modification dates — read-only here; reset them by re-exporting through a fresh PDF tool if needed.

Use cases

• Whitepaper publication — set a meaningful title before posting a download on your website.
• Anonymizing handoffs — strip the original author's username before sharing externally.
• SEO and DMS findability — accurate keywords improve internal search and certain web search behavior.
• Legal redaction support — metadata leaks have caused real legal incidents; clean before public release.

Privacy

Metadata edits happen in your browser using pdf-lib. Your PDF and its new metadata never leave your device. There is no telemetry of which fields you changed.

Complete PDF workflow with ToolAtom

This is one of ToolAtom's PDF tools. They all run in your browser with no upload, so you can chain them safely on confidential documents. Common workflows: scan or merge → rotate → add page numbers → watermark → protect, or unlock → edit metadata → re-protect for the next recipient.

• Rotate PDF — Fix the orientation of pages.
• Add Page Numbers — Number every page for printing or filing.
• Add Watermark — Stamp a DRAFT, CONFIDENTIAL, or brand mark.
• Protect PDF — Encrypt with a strong password before sharing.
• Unlock PDF — Decrypt a PDF whose password you know.
• PDF to Text — Extract plain text for analysis or accessibility.
• PDF to JPG — Render pages as images for slides or thumbnails.
• PDF Merger — Combine multiple PDFs into a single file.
• PDF Splitter — Break a large PDF into smaller files.
• PDF Compressor — Shrink file size for email and upload.

Related tools

People editing PDF metadata often also use Add Watermark to PDF, Add Page Numbers to PDF, Protect PDF, and Rotate PDF.