A forming method of a thermal insulation film, including: a first step of forming an anode oxidation coating film on an aluminum-based wall surface, the anode oxidation coating film including micro-pores each having a diameter of micrometer-scale and nano-pores each having a diameter of nanometer-scale; a second step of abrading a surface of the anode oxidation coating film with abrasive powders and bringing the abrasive powders into the micro-pores located at the formed abraded surface; and a third step of forming a protection film on the abraded surface to produce a thermal insulation film including the anode oxidation coating film and the protection film.