An object of the present invention is to suppress a blockage caused by oil particles in an upstream side of a filter in an oil removal apparatus that collects oil particles in a filter disposed between an anode and a cathode. While an internal combustion engine is operative, application of a voltage to a bipolar electrode is controlled such that a voltage application period, in which the voltage is applied to the bipolar electrode, and a voltage application stoppage period, in which application of the voltage to the bipolar electrode is stopped, are repeated alternately at predetermined periodic intervals.