To provide a pressing-force control device for a crushing type rotary tool, capable of uniformly dismantling gutter refractories.

A pressing-force control device for a crushing type rotary tool comprises, a hydraulic motor for swing to conduct the swinging operation of a boom, a drum elevating cylinder and a drum reciprocating cylinder 15, 16 for moving a drum 7 to a work position, stroke detectors 18, 19 for detecting the deviation of movement of the drum elevating cylinder and drum reciprocating cylinder 15, 16, a calculation means 20 for calculating a distance from the center line of swing of the boom to the drum 7 on the basis of the deviation of movement of the drum elevating cylinder and drum reciprocating cylinder 15, 16, which is detected by the stroke detectors 18, 19, and for calculating the movement moment of the drum 7 so that a pressing force of the drum 7 against gutter refractories reaches a fixed value preset, and a proportional relief valve 21 for modifying at least one of driving forces of the hydraulic motor for swing and the drum elevating cylinder and drum reciprocating cylinder 15, 16 on the basis of the movement moment of the drum 7, which has been calculated by the calculation means 20.