PURPOSE: To reduce the size of a cam body and eventually to reduce the weight over the entire part of the assembly.

CONSTITUTION: This drive assembly has the cam body 4 which carries out a rotational movement and a follower 5 which engages the cam body 4 and carries out the rotational movement. The assembly converts rotational movement to a pivotal movement. The cam body 4 is provided with a guide surface 11 formed with a closed curve and is so formed that the external shape E of this region constitutes an arc line. The follower 5 is engaged with the guide surface 11 and the axial center of rotation is nonrotatably connected to a shaft 6 passing the center of the external shape E.