A distance between a rotation center of an input member and a contact portion between an input side engaging portion and an input side engaged portion in a second direction is set to be shorter than a distance between a rotation center of an output member and a contact portion between an output side engaging portion and an output side engaged portion in the second direction. In a locked or semi-locked state, a contact portion between the output side engaging portion and the output side engaged portion is located on the side closer to the rotation center of the output member in a first direction in relation to a virtual line connecting the rotation center of the output member and a contact portion between one pressing surface of the pair of pressing surfaces and the pressed surface.