PURPOSE: To attain to enhance the efficiency of measuring work by displaying a measured distance on a reduced scale.

CONSTITUTION: A light emitter 2 projects projected light subjected to amplitude modulation by a modulated wave (a) generated by an oscillator 1 while the projected light 3 is reflected by the reflective mirror 4 at an objective point to reach a light receiver 6. The signal (b) generated from the light receiver 6 is supplied to a phase comparator 7 and the phase difference T with the signal supplied from the oscillator 1. The signal corresponding to the phase difference T generated from the phase comparator 7 is converted to a distance showing signal by a distance calculator 8. A weather correcting circuit 10 generates a signal for correcting a measuring error generated by the change of light velocity due to a weather condition to supply the same to an adder circuit 11 and a correction is added in the adder circuit 11 to display a signal for showing an accurate distance from a measuring point to an objective point by a display device 12. The output of the circuit 11 is also supplied to a reduced scale calculator 14 to be multiplied by coefficient selected by a reduced scale change-over switch 13. The data multiplied by cofficient is supplied to a display device 15 to display a reduced scale length.