Abstract: A sighting apparatus comprising an optical system which includes a laser oscillator and an automatic correction mechanism mounted on a rotational table, wherein the laser beams from the oscillator are emitted in any horizontal direction by remote control. A circular air bubble tube is provide on the table such that the position of an air bubble in the tube is sensed by a photosensor to recognize the tilt of the table. When the tilt of the table exceeds an effective operation range of the automatic correction mechanism, an interrupter circuit is operated to interrupt a power source circuit for the laser oscillator.