An internal gear pump for a slip-controlled hydraulic vehicle braking system includes a pinion, a ring gear, and a filler piece (sickle). The filler piece has an inner part extending in a curved manner in the peripheral direction and an outer part extending in a curved manner in the peripheral direction. The inner part and the outer part are interconnected in a hinged manner on the suction-sided ends. A leg spring is arranged between the inner and outer parts and is configured to separate the inner and outer parts and press against the tops of the teeth of the pinion and the tops of the teeth of the ring gear of the internal gear pump.