PURPOSE: To provide a method of controlling combustion in a waste material incinerator capable of continuing a stable combustion by a method wherein an amount of feeding waste material is detected in advance and a combustion condition is varied in response to the detected value.

CONSTITUTION: An electrical current of a dust dispersion machine 6 for feeding waste material 8 into an incinerator 10 is applied for detecting a variation of an amount of feeding waste material. When this feeding amount is substantially varied, an amount of primary air is reduced to perform a slow combustion at a fluidized bed 1, an amount of air corresponding to an amount of reduction of the primary air 2 is supplied to a location above the fluidized bed and then non-ignited material is ignited. Even if a feeding amount of the waste material is varied, the waste material 8 can be stably ignited.