Abstract: A machine tool has a holding portion, spindle, feed device, controller generating a position control signal according to machining data and controlling a feed motion of a drive unit according to the position control signal, reaction force detecting section for determining a reaction force the tool receives from the workpiece during machining, displacement amount calculating section for determining displacement of the tool with respect to a target control position based on the reaction force, and compensating section receiving the displacement amount and adding correction data for eliminating the displacement amount to the position control signal or the machining data.