To discharge a liquid by a simple construction.

A plurality of ink passages 13 with discharge ports 8 are formed in a head 1. On an ink passage defining surface 10b of the ink passage 13, a control electrode 18 extended towards the upstream side with respect to an ink flow direction from the discharge port 8, an insulating film 21 coating the control electrode 18, and an adjacent region 20 lower in liquid repellency than the insulating film 21 and adjacent to the upstream side with respect to the ink flow direction of the insulating film 21 are formed. A potential controlling part switches an electric potential of the control electrode 18 between a ground potential which increases the liquid repellency of the insulating film 21 so that a meniscus of ink is formed at the boundary between the insulating film 21 and the adjacent region 20, and a predetermined potential which decreases the liquid repellency of the insulating film 21 so that the ink is discharged from the discharge port 8 without a meniscus of ink being formed at the boundary between the insulating film 21 and the adjacent region 2.