A manufacturing method of an iron core product includes: heating an iron core body attached to a jig together with the jig; removing the iron core body from the jig when the jig and the iron core body are heated to denote a first temperature; and separately cooling, after removing the iron core body from the jig, the iron core body and the jig such that the iron core body is at a second temperature lower than the first temperature and the jig is at a third temperature lower than the first temperature.