To provide an automatic starter for providing the stable acceleration rotation of a crankshaft by keeping constant the power accumulation amount of a spiral spring in starting by using a small-capacity motor.

In this spiral spring type starter device for a small-sized internal combustion engine, a spiral spring type rotational energy accumulating means is provided with a spiral spring which is stored in the casing of the accumulating means, whose end part on an outside diameter side is locked on the casing, and whose end part on an inside diameter side is locked on a starter shaft, and a mechanism for releasing restraint of the starter shaft by sensing such a state that the spiral spring is caught.