A method for manufacturing a liquid ejection head includes the steps of: disposing an etching mask layer on a substrate having a first face and a second face that is on an opposite side of the first face, the etching mask layer being disposed on the second face; forming a concave line pattern at a region of the etching mask layer other than a region where an opening for the support port is to be formed; providing an etching opening at the etching mask layer; performing anisotropic etching from a side of the second face using the etching mask layer provided with the etching opening as a mask, thus forming the supply port at the substrate; comparing the line pattern with a recess generated at the substrate, thus selecting a device chip for liquid ejection; and connecting the selected device chip to a liquid supply part.