To provide a camshaft that neither score press-fit surfaces in an assembly process nor lower joining strength.

The camshaft is assembled by pressing a shaft into shaft hole in a cam piece. Grooves are formed in the inner periphery of the cam piece, and teeth are formed on the outer periphery of the shaft at intervals in the axial direction, thereby allowing the grooves in the cam piece and the teeth on the shaft to be engaged with each other. The teeth of the shaft are pressed into grooves in the cam piece at intervals in the circumferential direction. The grooves in the cam piece consist of press-fitting tooth grooves into which the teeth of the shaft are press-fitted, and non-press-fitting grooves larger than the press-fitting tooth grooves into which the teeth are not press-fitted.