A method for manufacturing a liquid ejection head includes forming a first negative photosensitive resin layer containing a photopolymerizable compound and a photopolymerization initiator over a substrate, exposing the first negative photosensitive resin layer to light to form a latent image of a flow channel member, forming a second negative photosensitive resin layer containing a photopolymerizable compound and a photopolymerization initiator over the first negative photosensitive resin layer having the latent image, and exposing the second negative photosensitive resin layer to light to form a latent image of an ejection opening member. The first negative photosensitive resin layer has a thickness of 10 μm or less and further contains a sensitivity adjusting agent capable of reducing the sensitivity of the first negative photosensitive resin layer. The transmittance A of the first negative photosensitive resin layer is 0.70 or less for the exposure light for the second negative photosensitive resin layer.