A method for manufacturing a ferromagnetic-particle includes preparing a manufacturing apparatus including an induction heating coil; a radiofrequency power source electrically connected to the induction heating coil and configured to form an alternating field inside the induction heating coil; a pipe disposed to pass through the induction heating coil, in which at least a partial area of the pipe in an axial direction thereof is formed of a dielectric material and an area, which is nearer to one end of the pipe than the area formed of a dielectric material, is formed of a conductive material; and a pump configured to introduce, from the one end of the pipe, an alkaline reaction liquid in which metal ions of a ferromagnetic metal and hydroxide ions are dissolved; reacting the reaction liquid in the pipe, introduced by the pump, by forming an alternating field inside the induction heating coil; and generating the ferromagnetic-particle in the pipe based on the reaction of the reaction liquid in the pipe.