Distance measuring apparatus

A distance measuring apparatus for measuring a distance to a target point in a target area comprises a laser oscillator for generating a laser beam having a first wavelength, a nonlinear crystal into which the laser beam having the first wavelength generated by the laser oscillator enters, the nonlinear crystal generating a laser beam having a second wavelength, a collimator lens at which the laser beam having the first wavelength generated by the laser oscillator and the laser beam having the second wavelength generated by the nonlinear crystal are concentrated and are transformed into parallel light flux, a laser device provided with the laser oscillator, the nonlinear crystal, and the collimator lens, an output unit for outputting the laser beam having the first wavelength and the laser beam having the second wavelength at the same time, which are emitted by the laser device, while scanning the target area, a selective reflective mirror for selectively reflecting the laser beam having the first wavelength and the laser beam having the second wavelength that are reflected at the target point in the target area, a first light receiving unit which receives the laser beam having the first wavelength selected at the selective reflective mirror and outputs a first signal, a second light receiving unit which receives the laser beam having the second wavelength selected at the selective reflective mirror and outputs a second signal, and a signal processing unit for measuring the distance to the target point in the target area by selecting one of the first signal and the second signal.