An on-demand type ink jet print head having a nozzle plate which is arranged horizontally so that its nozzle openings face upward and cantilevered vibrating members the free ends of which confront the nozzle openings. Ink is held by a capillary force in a gap between the vibrating members and the nozzle plate and is supplied by surface tension in a gap formed between a plurality of members from an ink tank up to the vicinity of the vibrating members. Since the ink is supplied by a capillary force between the ink level in the tank and the vibrating members, the ink supply is stable irrespective of the ink level in the tank. Further, since the ink is ejected in the form of ink droplets produced by a dynamic pressure associated with vibration of the vibrating members within the ink, it is possible to produce fine ink droplets.