The present invention enables the manufacture of a trochoid pump having a crescent which has been considered theoretically impossible by employing an inner rotor of a trochoid pump. An inner rotor having a predetermined number N of teeth that is equal to or larger than 4 is formed in advance. In order to manufacture an outer rotor with a predetermined number (N plus a natural number equal to or larger than 2) of teeth, row circles that are identical to a drawn circle are disposed so as to bring the row circles into contact with the tooth bottomland of the inner rotor tooth profile, the inner rotor tooth profile is rotated by half a tooth about the center of the inner rotor and the outer rotor tooth profile is also rotated by half a tooth of the predetermined number (N plus a natural number equal to or larger than 2) of teeth about a virtual center of the outer rotor including the row circles, an established center is determined from the virtual center or the like at the time at which the contact state is assumed, a reference circle is drawn that has a radius from the established center to the row circles and that has the total predetermined number (N plus a natural number equal to or larger than 2) of the equidistantly spaced row circles to form the row circles as outer rotor tooth tips, thereby manufacturing the outer rotor tooth profile.