A headrest includes: a main frame, left and right side frames, and left and right rotation-coupling portions. The main frame is supported at an upper end portion of a seatback. The left and right side frames that are disposed on left and right sides of the main frame. The left and right rotation-coupling portions couple the left and right side frames to the main frame such that the left and right side frames are capable of rotating with respect to the main frame about left and right up-down-extending axes. Each rotation-coupling portion includes a boss hole, a boss, a hinge hole, and a hinge.