A tape cartridge is mounted on a mounting section of a tape printer. The tape printer has an identification portion configured to identify a type of cartridge containing a tape-shaped printing medium. The tape cartridge includes a tape roll around which the printing medium is wound, a core shaft portion that rotatably supports the tape roll, and a fitting portion that is disposed at an inner circumferential side of the core shaft portion and is fitted to the identification portion when the tape cartridge is mounted on the mounting section of the tape printer. The fitting portion is disposed in a depressed portion that is configured to accommodate the identification portion when the tape cartridge is mounted on the mounting section.