Abstract: A fluid-filled active vibration damping device including: a pressure-receiving chamber partially defined by an elastic body; an oscillating fluid chamber partially defined by an oscillating rubber plate on one side thereof; a first orifice passage for a fluid communication between the pressure-receiving and oscillating fluid chamber, which are filled with a non-compressible fluid; and a working air chamber partially defined by the oscillating rubber plate on the other side thereof, to which an air pressure variation is applied to cause an oscillation of the oscillating rubber plate. A ratio V/Q of a passage volume V of the first orifice passage to a unit flow amount Q of the fluid through the first orifice passage caused by the oscillation of the oscillating rubber plate based on the air pressure variation applied to the working air chamber is held within a range of about 1-10.