Abstract: A laser positioning and measuring system for an earth boring apparatus is disclosed which includes a unique measuring unit comprising a pair of lasers mounted in a back-to-back relation with targets at their free ends. The targets include a beam passage through which laser beams from the measuring units are emitted. The emitted laser beams strike a target on an adjacent measuring unit. The area of which the laser beam impinges upon the adjacent targets generates a signal to indicate the displacement of the laser beams with respect to the adjacent targets to provide a coordinate and angle signals. The signals are processed in the computer to indicate deviations between the measuring units. The measuring units are spaced along the bore, for example, by attachment near the joints of the individual pipe casings which are pushed through the bore by the earth boring apparatus.