To provide a method for accommodating changing of gas type in which a packing member essential for sealing operation in a combustion device is utilized as it is, and a changing of flowing resistance which becomes necessary when a gas type is changed can be performed in less-expensive manner.

In a method for accommodation against changing of gas type in a combustion device in which there are provided two supplying sections having gas supplying passages for supplying fuel gas to a combustion section of the combustion device and a packing member is held between the two supplying members so as to cause the gas supplying passages of the two supplying members to be communicated to each other and fixed to them, a plurality of kinds of packings 26 for limiting a fuel gas supplying amount in the gas supplying passages to a different supplying amount are prepared, the plurality of kinds of packings 26 are selectively used and then the changing of gas type corresponding to the type of gas to be used is accommodated.