On a surface of an object to be treated, a Mn-containing thin film or CuMn-containing alloy thin film is formed by heat treatment (CVD or ALD) by using a Mn-containing source gas (or Mn-containing source gas and a Cu-containing gas) and an oxygen-containing gas (for instance, water vapor) as a processing gas. The Mn-containing thin film or the CuMn-containing alloy thin film can be formed with high step coverage in a fine recess formed on the surface of the object to be treated.