To solve the subject that alignment with an object to be measured takes time and effort.

This electromagnetic interference wave measuring apparatus is equipped with an ultrasonic echo sounder receiver 14 installed on a magnetic field probe 20, and three or more ultrasonic transmitters 15-17 for discharging ultrasonic waves to the receiver 14. Three-dimensional position measurement of the probe 20 is performed from a landing time of the ultrasonic waves from the three or more transmitters 15-17 to the receiver 14.