reverse identifying circuit 57 which issues normal rotation pulse and reverse rotation pulse the normal reverse identifying circuit 57 is connected to the pulse motor driver 58 via the gate circuits 56 and 55 and the pulse motor driver 58 drives the focusing motor 40 the surveyor turns the coarse adjustment knob 46 among the focusing knobs 45 and performs coarse adjustment by turning the coarse adjustment knob 46 at any angles with the rotation of the coarse adjustment knob 46 the coarse control switch 50 is rotated by the angle corresponding to the rotation angle of the coarse adjusting knob 46 when the coarse control switch 50 is turned at said angle voltage proportional to the rotation angle is outputted and the output voltage is outputted to the v f converter 53 and the comparator 52 the v f converter 53 converts the output voltage to a pulse with frequency corresponding to the absolute value and the comparator 52 inputs positive or negative value of the output voltage to the normal reverse identifying circuit 54 in response to the input from the comparator 52 and the v f converter 53 the normal reverse identifying circuit 54 inputs the normal rotation pulse or the reverse rotation pulse to the pulse motor driver 58 via the gate circuits 55 and 56 thus the focusing motor 40 is rotated in normal or reverse direction as desired and at a speed as desired the normal rotation pulse or the reverse rotation pulse is sent to the focusing motor 40 and the focusing motor 40 is.