Method of manufacturing liquid ejection head and method of forming resist

A method of forming a resist comprising:

• a step of forming a light-transmitting dissolving layer, which dissolves in a predetermined solvent, on a first surface of a light-transmitting support having the first surface and a second surface which is a back surface of the first surface;
• a step of forming a resist film on a back side of a surface of the dissolving layer on the support side;
• a step of bonding a substrate to a back surface of a surface of the resist film on which the dissolving layer is formed;
• a step of exposing the resist film with light transmitted from the second surface to the first surface of the support and further transmitted through the dissolving layer and forming a portion which is removable with a dissolving liquid and a portion which remains against the dissolving liquid on the resist film;
• a step of immersing the substrate, the exposed resist film, and the dissolving layer in the dissolving liquid, dissolving the dissolving layer with the dissolving liquid, and removing the removable portion and the dissolving layer by allowing the dissolving liquid to enter between the support and the resist film;
• and
• a step of peeling the support from the resist film from which the removable portion and the dissolving layer have been removed.