To shorten the length in an axial direction of a transmission.

A structure of a working fluid passage to the fasten element within a transmission is formed such that in the feed of working fluid from the internal part of an input shaft 1 to a rotary member 9 in a U-shape in cross section to contain a clutch piston 11 for forward, the inner peripheral end side of a wall-form member 8 to be joined with the bottom 15 of the rotary member 9 and support the partition wall of a line pressure fluid chamber 10 on the moving sieve 4 side is folded to the moving sheave 4 side, a gap is provided between the bottom 15 of the rotary member 9 and the wall-form member, the gap forms a clutch pressure introduction passage 18, a fluid passage 19 is formed in the bottom 15 of the rotary member 19, and a fluid pressure is fed to the piston 11. In this case, the seal position of the piston 11 is caused to approach the bottom 15 side to shorten the length in an axial direction of the piston 11, and by shortening the length in an axial direction of the rotary member 9, the length of a whole is shortened.