Abstract: A tape cassette generally comprises a case body composed of upper and lower case halves, a front lid mounted to the case body, a mechanism mounted in the case body for locking the front lid, and a chamber in which the locking mechanism is mounted. The locking mechanism includes a lock plate which is mounted in the chamber so as to be swingable. The lock plate is provided with a locking claw, a projection on the front surface thereof so as to outwardly extend therefrom, and a position limiting member formed of an elastically deformable material and secured on a rear surface of the lock plate so as to extend therefrom. The position limiting member has an extended end which abuts against a projection formed to one of the pivot pins rotatably supporting the front lid at both side ends to limit an outward locking position of the lock plate.