A light source module is provided. The light source module includes a light emitting element; a module substrate on which the light emitting element is mounted; a support member comprising a position reference section; and a fixing member which fixes the module substrate to the support member. The module substrate includes a positioning section which determines a position of the module substrate; and a displacement force generation section which imparts a displacement force onto the module substrate so as to bring the positioning section into contact with the position reference section of the support member when the fixing member is fastened to the support member.