Scribing characteristics of sapphire by using THG:YAG laser were experimentally investigated. The influence of polarization plane of laser beam on the curved shape at the tip of groove was also discussed. The absorptivity of laser beam at a high pulse repetition rate was still kept at higher order, altho ugh the feed rate became high. Therefore, a high pulse repetition rate condition is very effective for laser scribing of sa pphire. The curved shape at the tip of groove was greatly influenced by the direction of polarization plane of laser beam. This phenomenon occurred not randomly but regularly depending on the angle of polarization plane. The laser beam was strongly reflected in the direction of curved shape generation, in other words, in the perpendicular direction to the polarization plane of laser beam. Therefore, a suitable setting of polarization plane could make a straight groove without the occurrence of curved shape.