Abstract: Provided is a method for manufacturing a liquid ejection head substrate and a method for manufacturing a liquid ejection head capable of reducing degradation of the quality of a printed image. To this end, in formation of a liquid ejection head substrate, a part required to have more precise relative positional relation or not required to have high fabrication precision is set as a first part, and for the first part, a single-shot exposure method is employed. Also, a part required to have higher fabrication precision is set as a second part, and for the second part, a split exposure method is employed.