A three-dimensional tracer control system which is provided with an integration circuit for integrating the difference between a Z-axis direction displacement signal and a reference displacement signal and an adder for adding together the above-mentioned difference and the output from the integration circuit. The trace velocity in the Z-axis direction is controlled by the output from the adder, by which it is possible to perform tracing, with the Z-axis direction displacement signal and the reference displacement signal held nearly equal to each other; consequently, machining accuracy is increased.