A clutch includes a rotatable inputting member (1), a rotatable outputting member (2), a stationary member (3), and a contact member (5). The outputting member includes an output contact portion (2b). The contact member is positioned between the outputting member and the stationary member and includes an arcuate first contact surface (5b) and a second contact surface (5d). When the input torque for rotating the inputting member is inputted, the outputting member and the contact member rotate in contact with the inputting member. When a reverse input torque for rotating the outputting member is inputted, the outputting member is spaced from the inputting member, and the output contact portion (2b) of the outputting member urges the first contact surface (5b) against the stationary member by urging the second contact surface (5d) of the contact member thereby to prevent rotation of the outputting member.