PURPOSE: To manufacture an ink jet head passage plate which reduces the mutual, interference and carries out the high grade printing by emitting excimer laser beam in areas narrower than the width of channel formed by a mask and the like and repeating the above-said processing in a plurality of emissions when a very fine channel is formed on a passage plate of resin material by the excimer laser beam abrasion.

CONSTITUTION: A manufacturing method comprises a laser beam 1, a mask 2, a passage base 3 and parts 4 to be removed, and when the emission is controlled or projected in areas narrower than the width of channel formed by a mask, a lens system and the like, the depth of processing can be carried out in proportion to the number of times of emission. Then the emission position is changed by moving the passage plate or an optical system of laser, and emission is applied in a similar manner as above and sections are removed. A passage with step-shaped sectional profile is formed by repeating the above arrangement. A straight tapershaped sectional profile is formed out of the step-shaped sectional profile by reducing the pitch for changing the emission positions in the process. As the processing is carried out in the units smaller than the width of channel to be formed, a passage channel with tapered sectional shape can be formed.