Abstract: Disclosed is a methane engine for rocket propulsion. A methane supply pump (36) operated by a turbine (30) supplies a part of methane to a nozzle cooling channel (56, 156) installed on a nozzle (54, 154) of a combustor (50, 150) and supplies the other part of the methane to a combustion chamber cooling channel (53, 153) installed on a combustion chamber (52, 152) of the combustor (50, 150) so as to regulate the amount of methane supplied to a mixing head (51, 151) while maintaining the cooling properties of the combustor (50, 150), thus providing extensity of coping with changes in propulsive force and design of the combustor (50, 150). Further, a part of methane in a gas state discharged from the combustion chamber cooling channel (53, 153) is supplied to a mixing head (76) of a gas generator (94), thus providing the re-liability of the engine.