Provided are a laser processing apparatus and a method of establishing processing conditions of a substrate with patterns. According to the processing condition establishing method, laser is irradiated, in a disperse manner, along processing projected lines by processing marks formed on a substrate with patterns through unit pulse lights, and single chip operation of the substrate with patterns is achieved by crack extension processing enabling cracks of the processing marks. The method includes a step of crack extension processing serving as transient processing of a part of the substrate with patterns, and a step of defining the direction enabling rotation of an illumination lens during crack extension processing on the basis of a difference between a specific terminal position coordinate of a first photographing image, obtained by processing mark extension cracks formed by transient processing, when a transient processing execution position is photographed under a condition that a focus is directed at the
