A starter for an engine is provided which includes an electromagnetic brake device and a pinion thrust mechanism. The electromagnetic brake device holds a planetary carrier from rotating. The pinion thrust mechanism converts rotational motion of an internal gear into linear motion of a pinion when the rotation of the planetary carrier is locked. The pinion thrust mechanism includes a cylindrical cam cylinder, a starter housing, a thrust collar rotatable relative to the pinion, and an engaging pin. The cam cylinder is joined to the internal gear and has a circumferential extending cam groove. The starter housing has a straight groove traversing the cam groove. The engaging pin engages both the cam groove and the straight groove and is moved linearly with rotation of the cam cylinder. This enables the linear movement of the pinion regardless of a helix angle of the spline mounted on the output shaft.