Laser processing apparatus, and processing method for a workpiece using the same

Provided are a laser processing apparatus and a processing method for a workpiece using the same. The laser processing apparatus reduces uniform processing precision when processing at two orthometric directions is performed even the outline of a light beam is not isotropy relative to a processing direction. The optical system of the laser processing apparatus comprises a branch mechanism which divides a laser emitted from a laser source into a first branch light and a second branch light, a converting mechanism which makes the beam outline of the second branch light rotate 90 degree around the processing direction, a light path sharing mechanism which shares the light path of the first branch light and the light path of the second branch light passing the converting mechanism a illumination-used light path until reaching a condensing lens, a selective blocking mechanism which selectively blocks the first branch light and the second branch light between the branch mechanism and the light path sharing mechanis