A driving wheel supporting rolling bearing unit comprising: a stationary side bearing ring member supported and fixed to a suspension device to be non-rotatable; a rotation side bearing ring member configured to rotate together with a vehicle wheel while supporting and fixing the vehicle wheel; a plurality of rolling elements rollably provided between peripheral surfaces of the stationary side bearing ring member and the rotation side bearing ring member which face each other; a rotation side flange provided on a part of the rotation side bearing ring member and configured to support and fix the vehicle wheel; an internal gear fixed to the rotation side flange and configured to rotate together with the rotation side flange so as to configure a reduction gear, wherein the rotation side bearing ring member is rotationally driven based on a driving force input through the internal gear, characterized by an electric generator including a stator supported by the stationary side bearing ring member and a rotor supported by the rotation side bearing ring member, and configured to generate electric power based on relative rotation between the stator and the rotor; and a wireless communication device configured to wirelessly communicate with an electronic equipment disposed on a vehicle body side, the electric generator and the wireless communication device being disposed in an accommodating space at an axially inner side of the rotation side bearing ring member, wherein an axially inner end opening of the stationary side bearing ring member is covered by a cover formed of a radio wave permeable material, and a space inside the cover is the accommodating space. a stationary side bearing ring member supported and fixed to a suspension device to be non-rotatable; a rotation side bearing ring member configured to rotate together with a vehicle wheel while supporting and fixing the vehicle wheel; a plurality of rolling elements rollably provided between peripheral surfaces of the stationary side bearing ring member and the rotation side bearing ring member which face each other; a rotation side flange provided on a part of the rotation side bearing ring member and configured to support and fix the vehicle wheel; an internal gear fixed to the rotation side flange and configured to rotate together with the rotation side flange so as to configure a reduction gear, wherein the rotation side bearing ring member is rotationally driven based on a driving force input through the internal gear, characterized by an electric generator including a stator supported by the stationary side bearing ring member and a rotor supported by the rotation side bearing ring member, and configured to generate electric power based on relative rotation between the stator and the rotor; and a wireless communication device configured to wirelessly communicate with an electronic equipment disposed on a vehicle body side, the electric generator and the wireless communication device being disposed in an accommodating space at an axially inner side of the rotation side bearing ring member, wherein an axially inner end opening of the stationary side bearing ring member is covered by a cover formed of a radio wave permeable material, and a space inside the cover is the accommodating space.