A tape cassette 30 includes a cassette case 31 that houses a tape. An arm indicator portion is provided on an arm front surface 35 of the cassette case 31. The arm indicator portion includes vertical information sections extending along a direction orthogonal to a tape feed direction and an aperture formed in at least one of the vertical information sections, and indicates a tape type. A person can identify the tape type by visually checking whether an aperture is formed in each of the vertical information sections. A platen holder of a tape printer 1 includes detecting switches 210 at positions corresponding to the arm indicator portion of the tape cassette 30 installed in the cassette housing portion 8. The tape printer 1 can identify the same tape type as identified by the visual check based on detection results of the detecting switches 210.
