PURPOSE: To form a coated layer excellent in rate of oil removal with good adhesion, by adding a binder having soluble silicate as a substrate and a zinc oxide, etc., as a setting agent, to a self-purifying type catalyst.

CONSTITUTION: For the internal wall of a food cooking appliance, such as an microwave oven, an oxide of transition metal of the group IV in the periodic table is carried on ≥99.6% active alumina of high purity to obtain a self-purifying type catalyst. In this case, a binder is added which has soluble silicate as a substrate and a zinc oxide, aluminum phosphate, etc., as a setting agent. The coated layer obtained in this way has an excellent rate of oil removal, high adhesive strength to an article and excellent mechanical characteristics.