The present invention provides a manufacturing method of a substrate for an ink jet head including forming an ink supply opening to a silicon substrate, including (a) forming, at the back surface of the silicon substrate, an etching mask layer, which has an opening that is asymmetric with a center line, extending in the longitudinal direction, of an area on the surface of the silicon substrate where the ink supply opening is to be formed; (b) forming a non-through hole on the silicon substrate via the opening on the etching mask layer; and (c) forming the ink supply opening by performing a crystal anisotropic etching to the silicon substrate from the opening.