To reduce the rates of hydrocarbon and carbon monoxide contained in exhaust gas in an internal combustion engine after the engine is burnt by controlling a timing of a fuel injection according to an operating condition of a combustion type heater.

In a combustion type heater 17, a combustion operation is hastened and oxidation reaction is advanced since a timing of a fuel injection timing is hastened as the output of the heater 17 is larger. The rates of hydrocarbon and carbon monoxide contained in exhaust gas in an engine 1 are reduced compared with when an output of the heater 17 is small. Since a lean NOx catalyst 39 is arranged in an exhaust device 7, hydrocarbon and carbon monoxide contained in exhaust gas are used as reducer of the lean catalyst 39. As a result, the rates of hydrocarbon and carbon monoxide contained in exhaust gas in the engine 1 are further reduced, and a rate of nitrogen oxides contained in exhaust gas in the engine 1 is also reduced.