According to an embodiment, a manufacturing method of a semiconductor device includes: carrying a substrate alternately stacked an electrode layer and an insulation layer into a chamber; increasing the temperature in the chamber to a predetermined temperature; and supplying hydrogen and material gas including metal simultaneously into the chamber, and supplying oxidizing gas the partial pressure ratio of which to the hydrogen is set so as to provide an atmosphere of reducing the electrode layer, by using an ALD method, and thereby forming, on a surface of the electrode layer and a surface of the insulation layer, a metal oxide layer obtained by oxidizing the metal.