Provided is an inspection apparatus that has a plurality of electrically conductive intermediate plates and is used to inspect the power generation performance of unit cells of a fuel cell each disposed between the intermediate plates. The inspection apparatus has an oxidation gas supply manifold formed as through-holes provided in the unit cells and through-holes provided in the intermediate plates communicate with one another, and through which an oxidation gas is supplied into the unit cells. In a stacking direction of the intermediate plates and the unit cells, the oxidation gas is supplied from one end that is open. The oxidation gas supply manifold has water drain holes that extend downward and are respectively formed on an outer side of the unit cells located at both ends in the stacking direction, and the water drain holes are coupled to each other on a lower side of the water drain holes.