The method of manufacturing a liquid ejection head includes the steps of: forming a groove section in a first layer of a substrate including at least the first layer and a second layer, the groove section having a bottom face constituted by the second layer and being formed in a ring shape; forming a protective film on the groove section; forming a diaphragm on a surface of the first layer where the groove section is opened; forming a piezoelectric element on the diaphragm; forming an opening section in the diaphragm so as to expose a portion of a region of the first layer surrounded by the groove section; and etching the first layer via the opening section so as to form a pressure chamber, using the second layer as an etching stop layer.