In a machine tool having plural coordinates systems and having controlled objects controlled on the basis of those coordinates systems, a coordinate system data memory (310) storing the dimension information corresponding to each coordinate system as a coordinate system data is provided, a coordinate relation memory (313) storing the coordinate position relation information by which the position relation among plural coordinates systems is specified is provided, in case that the controlled object corresponding to each coordinate system is driven, the coordinate system data is read from the coordinate system data memory (310) when the coordinate system data belonging to the coordinate system except the coordinate system in which the controlled object is driven is needed, the read coordinate system data is converted from the coordinate system to which the corresponding coordinate system data belongs into the other coordinate system to which the controlled object belongs on the basis of the coordinate position relation information in the coordinate relation memory (313), and the controlled object is controlled on the basis of the converted coordinate system data.