An electromagnetic wave filter apparatus includes: a shield conductor; a shield aperture provided in the shield conductor; a plurality of strip conductors, each of which is connected to the shield conductor at both ends thereof, and which divide the shield conductor into a plurality of apertures; and a plurality of stub conductors provided at intervals on each of the strip conductors. Each of the stub conductors prevents a current with a predetermined frequency from flowing through a corresponding strip conductor due to an electromagnetic wave with the predetermined frequency passing through the electromagnetic wave filter apparatus. Thus, the electromagnetic wave filter apparatus passes the electromagnetic wave with the predetermined frequency without exerting a substantial influence on radiation of the electromagnetic wave with the predetermined frequency.