Heating device for external combustion engine

The invention provides a heating device for an external combustion engine, which is capable of improving stabilization of combustion in a control state with a relatively small quantity of heat and the property of an exhaust gas, and realizing long-time operation of the external combustion engine. To achieve this, a heating device 14 for an external combustion engine includes: a combustion housing 25 provided so as to surround a heating portion 11 of an external combustion engine E; an fuel-air mixer 27 provided at one end of the combustion housing 25 and an exhaust pipe 28 provided at the other end of the combustion housing 25; and an oxidation catalyst 26, disposed in the combustion housing 25, for accelerating combustion of a fuel-air mixture of a fuel and air supplied through the fuel-air mixer 27.