<p>A combustor is proposed which is compact and eliminates generation of NOx and unburned combustible and is capable of stable combustion. A combustor is accordingly provided which comprises a combustion section 11, a fuel supply section 12 coupled to the combustion section for supplying a fuel air mixture wherein the fuel supply section comprises a mixer of venturi tube type having a fuel supply port 25 on an inner peripheral surface of a throat part, a combustion air supply port 31 connected to a base end of the mixer of venturi tube type and an igniter made capable of generating a spark at an extremity of the mixer of venturi tube type and the combustion section comprises a frame 16 coupled to the boiler main body and a ceramic combustion tube 14 supported by the frame 16 via heat insulators 15a, 15b and 15c and having one end lying in communication with the extremity of the mixer of venturi tube type in the fuel supply section and the other end projecting into the boiler main body and wherein the ceramic combustion tube is made of a ceramic functioning as an oxidation catalyst.</p>
