The present invention provides a method for manufacturing a high quality ink jet head in which, in a case where a coating resin layer constituting ink flow path walls is formed, even when a solvent having a strong dissolving force is used, it is not feared that a configuration of an ink flow path pattern is distorted. In the method, a photosensitive resin composition layer in which an inter-molecule bridging reaction proceeds by irradiation of an ionization radiant ray having a first wavelength band and a molecule decaying reaction of main chain decomposing type of the resin proceeds by irradiation of an ionization radiant ray having a second wavelength band different from the first wavelength band is formed on a substrate on which energy generating elements were provided. Thereafter, an ink flow path pattern is formed by the irradiation of the ionization radiant ray having the first wavelength band and a developing process. Then, a coating resin layer constituting ink flow path walls is formed on the ink flow path pattern. After ink discharge ports are formed, the photosensitive resin composition layer forming the ink flow path pattern is dissolved and removed by irradiating the ionization radiant ray having the second wavelength band.