NOVELTY - Oxidizing agent gas is supplied from bottom of vertical gasifier (1) which is filled with waste material and having combustion zone (31) and decomposition zone (33) in order. The maximum temperature of the combustion zone is detected, by changing the extracting amount of combustion residue extracted from furnace bottom and carryingout measurement of temperature change of preset waste material quantity in furnace.    USE - For measuring temperature of combustion zone in moving bed-type gasifier used for processing of waste material.    ADVANTAGE - Exact maximum temperature of the combustion zone in moving bed-type gasifier is detected easily and stabilized gasification of waste material is enabled.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the waste material gasifier which has supply unit to supply oxidizing agent gas to the waste material filled gasifier. Several temperature sensors (20-23) of a thermometry unit arranged in the waste material filled in the furnace, detects the temperature change of the preset quantity of the waste material in the furnace. A rotary extracting unit (15) extracts combustion residue from the bottom of gasifier. The thermometry unit obtains the maximum temperature of the combustion zone based on the detected temperature, so as to control the extraction amount of the extracting unit. The supply unit controls supply amount of oxidizing agent based on maximum temperature of combustion zone. When thermometry unit detects maximum temperature of the combustion zone, extraction of combustion residue is started or stopped. Several temperature sensors (20-23) of the fo the are arranged in the waste material filled in the furnace.    DESCRIPTION OF DRAWING(S) - The figure shows a sectional view of the moving bed-type waste material gasifier. (Drawing includes non-English language text).    vertical gasifier (1)    combustion, decomposition zones (31,33)    rotary extracting machine (15)    temperature sensors (20-23)