PURPOSE: To detect the end of a magnetic tape wound on a hub by light signal transmitting/receiving means formed by using a pair of light emitting elements and light receiving elements.
CONSTITUTION: A light transmission part 7b is formed along the outer peripheral surface 7a of the hub 7 by using a transparent member allowing the transmission of the light from the light emitting elements 13. Further, 1st and 2nd reflection surfaces 7c, 7d are formed on both sides of the transparent member within this light transmission part 7b. A pair of the light emitting elements 13 and the light receiving elements 14 which are the light signal transmitting/receiving means are inserted into the hole 2b of the lower half 2 of a tape cassette 1A. On the other hand, the end of the magnetic tape 11 is fixed to the outer peripheral surface 7a of the hub 7. Incident light is emitted from the outer peripheral surface via the 1st and 2nd reflection surfaces 7c, 7d and is received in the light receiving elements 14 when the light from the light emitting elements 13 is made incident on the outer peripheral surface part of the light transmission part 7b where the magnetic tape 11 is not wound. The end of the magnetic tape 11 is thus detected.