Abstract: The invention provides a laser working method free from generation of by-products and capable of preventing accumulation of thermal energy generating during the laser working, in a workpiece made, for example, of a resinous material, thereby precisely reproducing a minute mask pattern, also a method for producing an ink jet recording head utilizing such a laser working method and an ink jet recording head produced by such a producing method. There is employed laser light in more than one pulse having a very high energy density in space and time, as emitted from a laser oscillator that can oscillate with a pulse radiation time not exceeding 1 picosecond, and a speckle interference image generated by light diffraction at the passing of the laser light through the mask pattern is dynamically changed to form an integrated image of the speckle interference image, whereby a pattern substantially the same as the mask pattern can be formed.