Abstract: A one-way clutch operates stably even while an engine is revolving at a speed that tends to resonate the springs of the clutch. The clutch has an outer ring formed with a plurality of cam surfaces on its inner periphery at equal intervals in the circumferential direction. An inner ring mounted in the outer ring has a cylindrical outer surface that faces the cam surfaces. Wedge-like spaces are defined between the cam surfaces an the cylindrical outer surface. Rollers and springs are mounted in the wedge-like spaces so that the rollers are biased by the springs toward narrower ends of the wedge-like spaces. The springs are made up of at least two different kinds of springs having different spring constants. Thus, even if one of at least two kinds of springs should resonate, the other springs will reliably keep the rollers locked between the cam surfaces and the cylindrical surface or move them to unlocked position. The life of the clutch is thus increased.