To provide a tape cassette 1 having a structure which allows a spindle 34 formed integral with a cover 3 to easily fit into a hole part 9a of a guide roller 9 mounted on the spindle 24 on the side of a case 2, when the cover 3 is fitted to the case 2, the structure preventing the surface 22a of the cover 3 formed with the spindle 34 from recessing, while keeping a molding die structure from becoming complex, and maintaining the durability of the spindle 34 even if tension applied to tape 6 is large.

At least the spindle 34 on the side of the cover 3 comprises a plurality of vertical walls 34b suspended from the inner surface of a base 34a and crossing each other at a joint 34a at different angles. At least one of the vertical walls 34b has its tip tilted so that the tip 34d of the spindle 34 is sharply formed in such a manner as to protrude toward the center of the guide roller 9.