A history of function values of a spindle rotation frequency in each time period from present to past is stored in a data table 22D and corrective coefficients are stored in advance in a corrective coefficient table 22C relating the coefficients to the location in the data table 22D. Each location and corrective coefficient are read out from the corrective coefficient table 22C and the function value of the spindle rotation frequency corresponding to the location is read out from the data table 22D. The compensation value is calculated from the total sum of each product of the function value and the corrective coefficient in each location and compensate the NC command position with the compensation value.