To obtain a clean exhaust gas property, a high radiation energy rate and a uniform combustion, by introducing a liquid fuel to a downstream of a non-like flowable porous member having air flowability while passing a combustion air introduced from its upstream to the member, and introducing a liquid fuel to the downstream of the member.

A body casing 1 holds a non-liquid flowable porous member 2 having air flowability and a combustion burner mat 3 disposed at a downstream side of the member 2. The member 2 has a temperature control thermocouple. A combustion air introducing port 4 is provided at the casing 1 of the upstream of the member 2, and a fuel tube 5 as an inlet of, for example, a liquid fuel such as a kerosene is provided at the casing 1 between the mat 3 and the member 2. To generate a premixed gas for supplying to the mat 3, the air is supplied from the upstream of the member 2 held at the casing 1, and the liquid fuel can be supplied from the downstream.