PURPOSE: To surely hold the locked state of a hub against vibration and impact, etc.

CONSTITUTION: Wedged hub locking pawls 14A and 14B provided in a hub locking member 13 contacting with/separating from a pair of hubs 20A and 20B round which a magnetic tape is wound with the turning action of a lid 4 turnably assembled on the front surface part of a tape cassette housing 1 and protecting the magnetic tape in a traveling path are engaged with a hub locking part 21 integrally formed on the side surface parts of the hubs 20A and 20B. Thus, the hubs 20A and 20B are prevented from idly rotating, and the hub locking part 21 is constituted as a slit 22 engaged so that the tip part of a hub locking pawl 14 may penetrate in an axial direction.