To accurately grasp a position of a surface fusion part in a burner type fusion furnace to be held in a proper position.

This burner type fusion furnace with the surface fusion part 20 of incineration ashes 5 formed in an exit 19a of a combustion chamber 19 in one side of a lateral-directed cylindrical fusion furnace main body 13, and with an oxygen burner 24 provided to direct a high-temperature jet flow 25 ranging over from the surface fusion part 20 to a well 16 is provided with a position detector 28 for detecting noncontactly the position of the surface fusion part 20 in the fusion furnace main body 13. A computation controller 29 is provided to input with a positional signal a detected by the position detector 28 and to compare it with a normal position of the surface fusion part 20 to issue a command. The computation controller 29 is connected to an oxygen supply line 30 to the oxygen burner 24 and flow control valves 32, 33 of an auxiliary fuel oil supply line 31. An amount of oxygen and an amount of the auxiliary fuel oil are increased or decreased based on positional information in the surface fusion part 20.