PURPOSE: To enable the application of a starter not only to a compact engine but also to a medium and a large engines and starting with low noise, by transmitting starting torque through an idle rotary shaft coupled to the output shaft of an engine by a belt, and through a friction clutch mechanism.

CONSTITUTION: When an ignition switch is put in a starting position, the conical portions 17, 20 of clutch members 11, 19 are put in contact with each other. At the same time, an armature output shaft 3 is rotated to turn the clutch member 19. Because of the contact of the conical portions 17, 20, the torque which rotates both the clutch members 11, 19 is applied to a spline tube 9 to make it about to rotate independently. As a result, the tube 9 moves rightward to push the clutch member 11 rightward to put the conical portion 17 in enough pressure contact with the other conical portion 20. Consequently, the tube 9 stops moving. Meanwhile, the torque which can be transmitted from a driving side to a driven side is also made high enough to start the rotation of a rotary shaft 6 together with the tube 9 to apply the torque of a starting unit 1 to a crankshaft to start an engine. A sufficient speed reduction ratio can be obtained in the capacity of a medium or large starter. Since the rotation after the starting is performed in a non-contact state, the noise is low.