In a tape cassette having sensor optical path holes provided on respective wall portions on a straight line coupling a position of a light emission element with a position of a light reception element so that light from the light emission element is introduced into a tape container and light passing through a tape running path of the tape container comes out of the tape container and reaches a light reception element, a light shielding member having a light shielding effect is bonded around a sensor optical path hole right after the light from the light emission element comes out of the tape container.