A method for manufacturing a semiconductor device includes: forming a first major electrode on a first major surface of a semiconductor substrate; forming a second major electrode on a second major surface of the semiconductor substrate opposite to the first major surface; carrying out a surface activating treatment to activate surfaces of the first and second major electrodes; carrying out a surface cleaning treatment to clean up the surfaces of the first and second major electrodes; and after the surface activating treatment and the surface cleaning treatment, simultaneously forming first and second Ni films on the first and second major electrodes respectively by a wet film forming method, wherein a ratio of crystalline Ni contained in the first and second Ni films is 2% or more.