To solve a problem of a small scale incineration kiln that installation of waste gas treatment equipment is structurally difficult so that the influence affecting surrounding environment cannot be neglected.

A firing kiln for roofing tile is utilized as follows: a duct is provided to send the waste gas from the exhaust part of the waste incineration apparatus into an air intake part in the firing zone of the firing kiln for roofing tile, and an exhaust vent is provided at the preheating zone of the firing kiln for roofing tile. Or waste is incinerated in the waste incineration apparatus during the operation of the firing kiln for roofing tile and the generated waste gas is introduced to the air intake part in the firing zone of the firing kiln for roofing tile through the duct and the waste gas is exhausted from the exhaust vent provided at the preheating zone of the firing kiln for roofing tile.