An electro-oculography apparatus 100 includes an eye potential measuring unit measuring an eye potential generated by an eye movement and outputting an eye potential original signal, and includes a minimum filtering unit 121 or a maximum filtering unit 123 each outputting a first eye potential signal by applying one of a maximum value filtering and a minimum value filtering to the eye potential original signal. The electro-oculography apparatus 100 also includes a maximum filtering unit 122 or a minimum filtering unit 124 each outputting a second eye potential signal by applying the other of the maximum value filtering and the minimum value filtering to the first eye potential signal.