A manufacturing method of a separator for a fuel cell is a method for forming a carbon coating film on a titanium substrate, which has a titanium oxide layer on a surface of the titanium substrate, by CVD. The method includes a step of making a state in which the titanium substrate, which has the titanium oxide layer on the surface of the titanium substrate, is placed into a vacuum atmosphere, an irradiation step of irradiating a surface of the titanium oxide layer of the titanium substrate with light having a wavelength of equal to or shorter than 390 nm before the carbon coating film is formed or while the carbon coating film is being formed, and a step of forming the carbon coating film on the surface of the titanium oxide layer that is irradiated with light in the irradiation step.