A method of manufacturing an optical element module 1 in which an optical element 8 and a semiconductor circuit element 9 are mounted on one surface of a silicon substrate 2, a mirror surface 2a inclined at approximately 45 degrees is formed on the other surface, and an optical fiber 7 facing the mirror surface is disposed in a V groove formed along the other surface, the method of manufacturing includes the steps of forming the mirror surface 2a and V-shaped side surfaces of the V groove simultaneously by first crystal anisotropic etching on the other surface, and forming an attaching surface 2b substantially perpendicular to the one surface and the other surface, which is formed at an end side of the V groove, and for attaching an end of the optical fiber 7, by second crystal anisotropic etching in a crystal plane orientation different from that of the first crystal anisotropic etching. Thereby, it is possible to realize an optical element module including an optical element that receives light or emits light, a semiconductor circuit element, and an optical fiber optically connected to the optical element, the optical element module highly-functionally performs an optical connection between the optical element and the optical fiber, and realize a method of efficiently manufacturing the optical element module.