Abstract: A manually operated sprayer which comprises a pump mechanism including a secondary valve having a valve body normally pressed against a valve seat by a compression spring and valve-sealing means designed temporarily to obstruct the flow of a liquid even after the valve body slides in liquidtightness along the inner wall of a tubular piston and is released from the valve seat, and wherein the valve-sealing means of the secondary valve is integrally formed with the valve body, and slides in liquidtightness along the inner wall the tubular piston for a prescribed distance to be brought into an annular groove formed in the inner wall of the tubular piston, thereby taking the form of a skirt-like strip to be released from the liquidtight condition.