To provide a petroleum combustion apparatus which makes it possible to completely burn by completely vaporizing mixed gas and to comfortably heat without generating odor by the complete combustion.

The petroleum combustion apparatus comprises an inner burner body 40 protruding from one side to the inside at the sidewall to easily preheat even by small heat quantity by reducing the inner volume, a nozzle pipe having a nozzle cap 47 to diffusion inject petroleum fuel in the body, and a venturi tube 41 fixed to the body and having an inlet and outlet formed in tapered state of two stages at the inside so as to rapidly discharge the combustion air by the venturi operation.