Disclosed is a laser processing apparatus and method for enhancing processing efficiency of an object by means of a polygon mirror. The laser processing apparatus includes a laser generator outputting a laser beam with a predetermined diameter, a polygon mirror rotating on an axis with plural reflection planes to reflect the laser beam incident on the reflection planes from the laser generator, in which the number of the reflection planes is set in order that the laser beam can cover at least two reflection planes of the polygon mirror, and a lens condensing and irradiating the laser beam reflected from the polygon mirror. According to the present invention, it is able to improve the processing efficiency and product yield of an object by dividing the laser beam into the plurality to be incident on the reflection planes of the polygon mirror and repeatedly processing the object in low energy by means of the divided laser beam.