To provide a via hole inspecting device capable of speedily, easily, and accurately detecting resin residues in via holes in a printed wiring board.

In the via hole inspecting device 1, via holes in a build-up substrate S in which insulating resin layers and conductor layers are laminated. The via hole inspection device 1 is provided with a light source part 2 provided with a plurality of semiconductor light emitting elements 21 for sequentially switching a plurality of rays of light with different center wavelengths with one another and irradiating the via holes with them, a light receiving part 3 provided with a plurality of two-dimensionally arranged light receiving elements for detecting reflected light from the via holes, and a signal processing part 4 for sequentially acquiring output signals from the light receiving part 3 according to the switching of the plurality of rays of light and determining the degree of resin residues in the via holes on the basis of the acquired output signals.