In a tape cassette housing including a lid which protects the tape at the front of the housing, and a lid locking member turnably pivoted in the housing and having two leg levers, one to lock the lid when the latter closes the front opening of the housing and the other to release the lid when the same is turned open, the distance between the rotational center of the pivot of the lid locking member and the crown of its head is longer than the distance between the center of pivot bearing in the housing and the rear wall of a space in which the lid locking member is mounted.