A method of manufacturing a liquid ejection head includes: exposing a negative organic resin layer to be a flow path forming member except for regions in which an ejection orifice and a fluid resistance portion are to be formed, respectively, and heating the negative organic resin layer and a flow path pattern to move a portion of the negative organic resin layer which corresponds to the fluid resistance portion toward a substrate; and exposing and developing the region of the negative organic resin layer in which the fluid resistance portion is to be formed.