PURPOSE: To produce a nozzle plate having nozzles having a cross-sectional shape high in rigidity and low in pressure loss by forming the nozzles of an ink jet head from a resin material at the same time when the nozzle plate is formed and subsequently irradiating the tips of the nozzles with ultra violet rays.

CONSTITUTION: A nozzle plate 10 is formed by injection molding and nozzles 11 are also molded at the same time. The flash 12 at this time is removed by ultraviolet rays 20 (e.g. excimer laser beam). An inclined surface 15 having an effect of reducing pressure loss and increasing the thickness of the nozzle plate is formed to each of the nozzles 11.