In a valve timing adjustment device, a first arm projection portion that is caught by a terminal hook portion of a spiral spring and urged toward a lock phase side by the spiral spring is installed on a face opposite to the front surface of a plate in a first arm in a case where a rotational phase of a second rotating body with respect to a first rotating body is on a first rotational phase side, and a second arm projection portion that abuts on an outermost peripheral portion of the spiral spring is installed on a face opposite to the front surface of the plate in a second arm in a case where the rotational phase is on the first rotational phase side.