PURPOSE: To detect the position of a talker and to trace it to control a camera of a visual telephone set.

CONSTITUTION: Ultrasonic wave speakers 3, 4 are provided on a receiver part of a handset 2 and an ultrasonic wave radiated from them is received by ultrasonic wave microphones 8-10. When a period of time after an ultrasonic wave is emitted till the wave is received by the ultrasonic wave microphones 8-10 is measured, the position of the receiver is located based on the principles of the triangulation. Since a talker 19 touches his ear onto the receiver, the approximated center position of the face of the talker 19 is a position somewhat deviated from the position of the receiver. Thus, the face of the talker 19 is traced by controlling a camera 18 so as to be directed in the approximated center position.