The present invention can finely arrange p+-type diffusion layers and n+-type diffusion layers. A p+-type diffusion layer 2 and an n+-type diffusion layer 3 are simultaneously formed on a back surface 1a of a semiconductor substrate 1 in a state that the p+-type diffusion layer 2 and the n+-type diffusion layer 3 are arranged close to each other, and a back surface 1a side of the semiconductor substrate 1 on which outer end portions of the p+-type diffusion layers 2 and the n+-type diffusion layers 3 are brought into contact with each other is removed thus separating the p+-type diffusion layer 2 and the n+-type diffusion layer 3 from each other and hence, the p+-type diffusion layer 2 and the n+-type diffusion layer 3 can be separately arranged in a state that the p+-type diffusion layer 2 and the n+-type diffusion layer 3 are arranged close to each other.