According to a gas table 1, combustion gas (including the flame) is jetted from a flame port 17 of a burner 14 diagonally upward entirely twisted in the burner circumferential direction. The combustion gas flows into plural combustion gas routes sectioned into spiral shape, and hits trivet claws 22, and goes through. That is, the combustion gas is guided in spiral shape by the trivet claws 22, and exhausted along a cooking container P bottom surface toward the outer circumferential direction. As a result, in the combustion gas route, the combustion gas is always subject to direction changing force and the flow thereof is disturbed, and accordingly, a heat transmission border film is unlikely to be formed on the cooking container P bottom surface, and the heat of the combustion gas is transmitted to the bottom surface of the cooking container P preferably.