1. An automatic surveying apparatus using a laser beam, comprising a laser device adapted to radiate a laser beam and installed at a datum point for surveying, and a moving target having at least one projection screen upon which the laser beam from said laser device forms a laser spot and an optical processing system adapted to take the laser spot formed on said projection screen and to detect the positional coordinates of the laser spot on the projection screen, whereby a positional deviation of the target relative to the laser device is automatically measured on the basis of the positional coordinates detected by the optical processing system.