According to the present invention, a pump housing (10) comprises sliding surfaces (12b, 18d) on which an outer gear (40) and an inner gear (30) slide, intake guide paths (13, 21) that are more recessed than the sliding surfaces and that extend in a circumferential direction, and outtake guide paths (15, 19) that are more recessed than the sliding surfaces and that extend in a circumferential direction. Intake-side edge portions (14, 22) of the intake guide paths and outtake-side edge portions (16, 20) of the outtake guide paths have an interval therebetween and face each other. In a deflection angle ([theta]s) at which contraction of a pump chamber (60) begins, of the outtake-side edge portions, outer circumferential portions (16a, 20a) are formed along inner teeth (42a) and inner circumferential portions (16b, 20b) are formed along outer teeth (34a). In the pump housing, a processing tool (72) that rotates and cuts in a circular form is moved circumferentially in a single stroke manner so as to form an outline of the outtake guide paths, thus forming the outtake guide paths and is moved circumferentially in a single stroke manner so as to form an outline of the intake guide paths, thus forming the intake guide paths.