A one-way clutch includes a first rotational member (11a), a second rotational member (11b) and a first rotational body (1a). The second rotational member (11b) has plural first through holes (11c) in which bolts (17) are inserted. A dimension of the first through hole (11c) is larger than a dimension of the first through hole (11c) in a radial direction. A first region and a second region divide the first through hole (11c) into two regions in the circumferential direction. The first region is located ahead of the second region when the second rotational member rotates relative to said first rotational member (11b) in a specific rotational direction. The bolts (17) are inserted such that the each of the bolts (17) is located in the first region of the first through hole (11c), and the second rotational member (11b) and the first rotational body (1a) are fastened by the bolts (17).
