A process for producing a liquid ejection head including a silicon substrate having a first surface and a second surface that is a surface on an opposite side to the first surface, an ejection energy generating element which is formed on a side of the first surface side and generates energy for ejecting a liquid, a cavity formed in the second surface and a liquid supply port which is formed in a bottom part of the cavity and communicates with the first surface, including, in the following order: (1) forming the cavity in the second surface of the silicon substrate by a first crystal anisotropic etching; (2) forming a chemical leading hollow in a slope of the cavity; (3) expanding the cavity by a second crystal anisotropic etching; and (4) forming the liquid supply port in a bottom face of the cavity by dry etching with the use of an ion.