To eliminate generation of a waste ink by detaching a cap member in a short time at the time of sucking by providing a one-way valve between a sucking cap and a suction pump.

A one-way valve 40 is provided in a tube connecting a cap member (sucking cap) 2 and a suction pump. In the case where the inside of the tube reaches a predetermined negative pressure by driving the suction pump, a spherical valve 650 moves downward, resisting the force of a pressure spring 655 so as to keep a valve open. As a result, a space part of the cap member 2 keep communication with the tube via through holes 640, 285 so that an ink in a nozzle is ejected as a waste ink by the negative pressure in the space part. Thereafter, the negative pressure in the tube is reduced with stop of the suction pump so as to reach a predetermined negative pressure, the spherical valve 650 closes the through holes by the force of the pressure spring 655. In this case, the time for detachment of the cap member 2 from a head after stoppage of the suction pump drive is substantially negligible.