PURPOSE: To operate a device easily with one person and to measure accurately the distance to a desired place by operating the distance between two measuring points on a basis of the difference of the transmission timing and the reception timing of a control signal.

CONSTITUTION: The radio signal radiated through a radio oscillating circuit 10 and a transmission antenna 6 is inputted to a radio receiving circuit 12 through a reception antenna 11. The circuit 12 outputs a start signal S1 to operate an ultrasonic transmission circuit 13, and an ultrasonic pulse U having a prescribed time width is transmitted from a transmitter 7. This pulse U passes a receiver 8 and an ultrasonic reception circuit 14 to output a pulse signal P1. The pulse signal P1 and a start signal ST are inputted to an arithmetic circuit 15, and digital data Da indicating the arithmetic result obtained on a basis of these two signals passes a correcting circuit 16, and the value of a distance D due to a corrected data Da' is displayed digitally. Consequently, the distance is measured with a very high accuracy.