In a laser array device, each laser of a transmitting unit 30 and each optical detector of a receiving unit 20 are arranged to be adjacent to each other. A plurality of unit modules 40 are formed so that each unit module 40 contains adjoining laser 30-1 and optical detector 20-1, and a laser control circuit 10-1. In each unit module, a part of laser beam outputted from the laser is reflected and outputted to the optical detector, an intensity of the laser beam outputted from the laser is detected based on a detection signal outputted from the optical detector, and when the detected laser-beam intensity exceeds a predetermined reference level, the output of the laser beam of the laser is stopped.