A clutch mechanism for a vehicle seat is provided. The clutch mechanism includes a pressure-receiving member rotatably assembled to a frame of a seatback, a connecting arm having a weight and provided rotatably to the pressure-receiving member, a first swinging member provided rotatably to the frame, wherein while inertia force occurring due to a crash of a vehicle from behind acts on the weight, when the pressure-receiving member rotates upon receipt of a seatback load of a passenger, the connecting arm causes the first swinging member to rotate; and a second swinging member provided rotatably to the frame of the seatback, and configured to rotate along with the rotation of the first swinging member. The second swinging member is held in a state achieved when the first swinging member rotates by a predetermined angle even when the first swinging member rotates by an angle larger than the predetermined angle.