To provide a laser drilling device with which a drilling of high quality is performed.

The device is provided with a focal point adjustment means which vertically moves and adjusts an fθ lens with respect to a work and a control part for focal point adjustment means, which controls the focal point adjustment means, and the drilling is performed with a plurality of pulse laser beams of which the focal points are varied by driving the control for the focal point adjustment means when one hole of the work is drilled. Thus, the quality of the drilled hole is assured.