To provide a spring for a one-way clutch having good engaging performance and dragging torque (friction torque) considerably smaller than conventional one.

Engagement members are arranged in a pocket arranged in a circular space between an outer ring and an inner ring and provided at a constant space in the peripheral direction. The spring 6 for the one-way clutch provided extending into the pocket for energizing the engagement members to the side of engagement has pawl portions 6c each of which has three meandering bent portions with their centers of curvature on the side of the inner ring on the basis of a circular base portion 6a as part of the spring. The engagement members 5 before arranged are previously bent inside. A height h2 of the front end of the pawl portion 6c from the base portion is greater than a height h1 of the peak of the second bent portion from the base portion, and the radii of curvature of the three bent portions are all formed in a range of 0.2 mm-0.6 mm.