Second etching is performed to the bottom through dry etching of a substrate to suppress image degradation even if an opening position of an ejection opening at a substrate end deviates. Provided is an inkjet printing head substrate including: a first surface, a second surface, and a plurality of ink supply openings, wherein the plurality of the heat resistive elements and the plurality of the ink supply openings are arranged in such a manner that each of distances between a heat resistive element closer to an inclined surface of the recessed portion in the inkjet printing head substrate among the plurality of the heat resistive elements and two ink supply openings adjacent to the heat resistive element is longer than each of distances between a heat resistive element closer to the center of the inkjet printing head substrate and two ink supply openings adjacent to the heat resistive element.