Patent ID: 7380739

Claim:
A magnetic tape cassette comprising: a case that is formed by joining an upper half and a lower half; a tape reel or tape reels around which magnetic tape is wound and which are housed in said case; a window through which the magnetic tape is visible and with which said upper half is provided; and a reel urging member having a tape reel contacting portion which contacts an upper part of said tape reel or each of said tape reels, bent arms connected to opposite sides of the tape reel contacting portion and sliding end portions provided at distal ends of the bent arms, wherein a slide groove along which said sliding end portions of said reel urging member slide is provided in an inner surface of a perimeter of a window opening in said upper half and a window member which is removably fitted in said window opening has hold-and-retain portions which hold said sliding end portions in cooperation with a bottom surface of said slide groove into which said sliding end portions have been fitted.