CAM GRINDER

PURPOSE: To highly efficiently perform a high-precision working very small in working error at the time of finishing an object to be worked by speedily converging the working error as much as possible. CONSTITUTION: Based on the deviation obtained corresponding to reference time at a present working position N, storage values in previously designated plural storage areas corresponding to reference time before the reference time at the present working position N are rewritten and stored. Besides, based on the respective stored values in the previously designated plural storage areas corresponding to reference time after the reference time at the present working position N, control data at the reference time at the present working position N are corrected. An amount A of separation from the storage areas corresponding to the reference time at the present working position N in the designated storage area is changed and set corresponding to the degree of the following delay of a grinding wheel base from a control command to a moving means. A number (n) of designated storage areas is changed and set corresponding to the degree of dispersion in a main shaft rotating angle at every reference time shown at every time of a grinding working operation each time a main shaft is once rotated.