Device and method for positioning processing tool

To make high-precision positioning possible without calculating the amount of deflection, using the rigidity value for a positioning device. A device for positioning a processing tool is provided with: a processing tool for processing the to-be-processed surface of a workpiece while pressing the surface to be processed; a movement mechanism able to displace the distal end of the processing tool in a first direction orthogonal to the surface to be processed and/or a second direction parallel with the surface to be processed; a force sensor able to detect a force in the first direction and a force in the second direction applied to the distal end of the processing tool pressed onto the surface to be processed; and a control device for executing a correction step for controlling the movement mechanism so the surface to be processed is pressed while the position of the distal end of the processing tool is aligned with a processing reference position on the surface to be processed, and correcting the position of the processing tool so that the force in the second direction, which is generated until the force in the first direction detected by the force sensor reaches a desired value, is within a specific value or less.