A vehicular transmission includes a gear-change mechanism section that shifts power from a driving source and outputs the power to an output shaft; and a hydraulic system that supplies hydraulic pressure from an oil pump to the gear-change mechanism section via a check valve. The check valve includes a cylindrical valve case in which a passage is formed, a valve stored within the valve case so as to be freely movable in an axial direction of the valve case, a valve seat that is formed at one end portion of the passage in the valve case and that closes the passage when the valve sits thereon, a spring for urging the valve so as to sit on the valve seat, and a spring seat fixed on an axially opposite side of the valve seat in the valve case to support the spring.