<p>The present invention discloses a tape cassette having a front lid for protecting a magnetic face of a magnetic tape accommodated in a casing made of upper and lower half members against dust or the like, and a connecting plate and a rear lid suspended from the connecting plate for protecting an upper portion and a lower portion of the rear face of the magnetic tape respectively. The front lid is rotatably supported at sides of the casing. The rear lid is rotatably suspended on the connecting plate which is rotatably supported on the front lid. The magnetic tape is protected between the front lid and the rear lids together with the connecting plate in a lid closed state. A pair of pins provided on the rear lid is snugly fitted in a pair of guide grooves formed in protruding portions provided in the lower half member so that the rear lid may move in opening and closing directions. The guide grooves have open tops so that the pins of the rear lid are easily inserted into the guide grooves in the assembly process. The open tops are covered with front rims provided on the upper half member in the assembly process. <IMAGE></p>