A command value generator includes: a target path and tolerance range changing unit changing at least one of the target path and a range of tolerance based on the machining error; a response path calculation unit calculating a response error and a response path; a path comparison unit calculating an error between the response path and the target path and determining whether the calculated error falls within the range of tolerance; a temporary command path holding unit holding the target path as a temporary command path; and a command path correction unit correcting the temporary command path. The temporary command path is corrected based on the response error when determining the calculated error not to fall within the range of tolerance, and a corrected temporary command path is held in the temporary command path holding unit.