PURPOSE: To rapidly shorten/enlarge the diameters of respective coil springs so that the responsiveness of a spring type one-way clutch can be improved by providing the coil springs to tighten an inner member, between the inner member and an outer member, dividing the coil springs into a plurality of unit coil springs, and connecting one end of each unit coil spring to the outer member.

CONSTITUTION: A plurality of dextral unit coil springs 2 are fitted to an inner member 1 having predetermined margines, and are stored inside an outer member 3. Engagement shaft parts 4 which are faced in a diametral direction are provided to one end of each unit coil spring 2, and are engaged with grooves 5 formed on the inner diametral surface of the outer member 3 so that respective unit coil springs 2 and the outer member 3 are rotated together. As each one end of each unit coil spring 2 whose number of windings is few, is connected to the outer member 3, force to strengthen or loosen for winding around coils rapidly affect the other end side of each unit coil spring 2, so that the diameters of respective unit coil springs 2 are rapidly shortened/enlarged.