PURPOSE: To facilitate the fixing to conventional internal-combustion engine and to enable the massproduction, by previously fixing bodies bearing preworked catalysts on a cylinder inner wall, cylinder head and piston head wall face or the non-sliding section of an internal-combustion engine and exhibiting the catalyst function.

CONSTITUTION: Low temperature contact oxidation is performed on a hydrocarbon in a flame-retardant layer to be formed on an inner wall face while holding the catalyst layer temperature below 500°C for an outer wall face cooling type internal-combustion engine while approximately 800°C for an insulation type internal-combustion engine, then it is burnt while agitating the fuel mixture in the proximity to transmit the reaction heat to the fuel mixture compressed in a combustion chamber. Furthermore a catalyst layer which is not required to withstand the high temperature higher than 1,000°C to be produced through the burning of general hydrocarbon compound is secured on the surface of a body to be fixed on the inner wall face at the non-sliding section of a piston in the combustion chamber of a reciprocal internal combustion engine.