To provide a three-dimensional ultrasonic digitizer system which uses a digitizer device having a painting device that outputs the ultrasonic coordinate signals and at least three receiving devices which receive these coordinate signals.

This digitizer system consists of a digitizer input part 1 which includes a reference signal generation means, an ultrasonic wave output element and a 2nd communication transmitting means, at least three ultrasonic wave receiving elements 2a, 2b and 2c, a 2nd communication receiving means 3 which receives the reference signal, and a digitizer device 5 which includes a reference signal generation means, at least three coordinate signal detection means, a time difference calculation means, a distance calculation means and a coordinate calculation means.