To acquire an intermediate estimation of respective estimated elements in comparison with a roller cam mechanism and a barrel cam mechanism, which have both merits and demerits, and to provide a cam mechanism flexibly responding to a permissible storage space.

A truncated cone 6 in which the rotary shaft (output shaft) 5 of a turret 4 becomes an axis is arranged on the turret 4, a cam follower 3 is arranged on the slanted surface of the truncated cone 6, an input shaft 2 direction of an input cam 1 is orthogonal to an output shaft direction of the turret 4, and a cam groove 7 or rib 9 of the input cam 1 is fitted in the cam follower 3. Thus, preload can be also applied on the cam mechanisms, so that a pressure angle at the time of a stoppage and the maximum pressure angle become intermediate between those of a roller gear cam and barrel cam, a dimensional ratio between a Y-direction and Z-direction is changed by changing the angle of the slanted surface, and the cam mechanisms is easily adjusted for the permissible storage space.