In a starter, a cylindrical tube is slidablly engaged with an outer peripheral surface of an output shaft through a bearing in an axial direction. A front end of the tube, which supports a pinion, is closed to define an enclosed space between the front end of the tube and an end of the output shaft. A ventilation groove is formed on an inner cylindrical surface of the tube to communicate the enclosed space with a space defined rearward of the bearing. The ventilation groove has a helical shape twisted about an axis of the tube. When the bearing is press-fitted in the tube, a direction of press-fitting the tube and a direction along the ventilation groove do not coincide, but cross each other.