Each of the step of forming a first variable resistance layer (18a) and the step of forming a second variable resistance layer (18b) includes performing a cycle once or plural times, the cycle consisting of a first step of introducing a source gas composed of molecules containing atoms of a transition metal; a second step of removing the source gas after the first step; a third step of introducing a reactive gas to form a transition metal oxide after the second step; and a fourth step of removing the reactive gas after the third step. The step of forming the first variable resistance layer (18a) is performed in a state in which the substrate is kept at a temperature at which a self-decomposition reaction of the source gas does not occur. One or plural of conditions used for forming the second variable resistance layer (18b) is/are made different from the one or plural conditions used for forming the first variable resistance layer (18a), the conditions being the temperature of the substrate, an amount of the introduced source gas and an amount of the introduced reactive gas.