Numerical controller capable of correcting a deviation amount of a workpiece

A numerical controller for correcting automatically an offset value corresponding to an offset number based on a deviation amount corresponding to a difference between a theoretical value and a measured value obtained on processing a workpiece, the numerical controller comprising:

• a machining unit for storing a machining path of the workpiece and the effective offset number during machining of the machining path in association with each other;
• a measurement unit for storing a deviation amount applied to the workpiece and a measurement point at which the deviation amount is detected in association with each other;
• and
• a correction unit for correcting the offset value corresponding to the offset number based on the deviation amount corresponding to the machining path around the measurement point,
• wherein the correction unit identifies the offset number at the time of the machining in a vicinity of the measurement point at which the deviation amount is detected, and corrects an offset value corresponding to the offset number associated with a path closest to the measurement point at which the deviation is detected.