An improved method and apparatus for drilling blind via holes to connect between upper conductive layers and lower conductive layers of printed wiring boards with laser lights. The resin layer contacting the targeted conductive layer is drilled to remain the residual layer with laser lights, and the residual layer is removed with a UV laser beam whose energy density is lower than the decomposition energy threshold of the conductive layer and higher than that of the resin layer. The apparatus for this drilling has at least two laser paths. The spatial energy distributions are made top-hat-shaped with beam homogenizer units in the paths, and the diameters and the energy densities are adjusted independently.