Provided is an internal gear pump requiring fewer machining steps, allowing inexpensive manufacture, and offering high safety from the standpoint of function. The internal gear pump 1 comprises: a trochoid 4 in which an inner rotor 3 having a plurality of outer teeth is eccentrically and rotatably accommodated in an outer rotor 2 having a plurality of inner teeth, the outer teeth meshing with the inner teeth, and in which a suction-side chamber for suctioning liquid and a discharge-side chamber for discharging liquid that has been suctioned into the suction-side chamber are formed in between the inner teeth and outer teeth; a casing 5 in which is formed a recess 5a for accommodating the trochoid 4; and a cover 6 for closing off the recess 5a of the casing 5. At least some of the casing 5 is a body injection-molded from a resin composition. The invention also comprises a groove 5d in a portion of the recess 5a of the casing 5 in which the outer periphery is sealed, with a sealing ring 13 installed therein, and bushings 7 made from sintered metal that are provided integrally during injection molding in bolt fixing hole portions.