To provide a liquid pressure-feeding device capable of smoothly and stably rotating a semicircular internal tooth planetary rotor in a round outer hull ring-shaped circle at a high speed.

This liquid pressure-feeding device A wherein the combination of the semicircular internal tooth planetary rotor in round outer hull ring-shaped circle and two semicircular external tooth rotors 4, 5 are defined by partitioning a fixed cylindrical part 2 having semicircles, has pairs of left and right liquid suction ports 15, 17 and discharge ports 14, 16 in the round outer hull 1, whereby the liquid pressure-feeding quantity can be increased, and the rotor 3 can be smoothly rotated at a high speed. Further the liquid pressure-feeding device A can be used in a reverse state by following the forward and backward rotation and the rotating direction by the external rotating power. Further the liquid of high pressure is pressure-fed and rotated to stably rotate the rotor 3 at a high speed, whereby high liquid pressure-feeding quantity and high output can be achieved.