PURPOSE: To prevent deterioration, burning, and breaking of a coil so as to lengthen the life of the coil by introducing unnecessary currents flowing to a yoke coil to a shunt circuit when letting pulse currents flow to the yoke coil for magnetization being load.

CONSTITUTION: An input terminal 7 is connected to the output terminal 5 of a magnetizer, and a yoke coil 6 is connected to an output terminal 10 being load, and when the currents of the magnetizer flow, controlled currents are let flow to the coil 6. In this constitution, a + input terminal 7 connects directly with at + output terminal 10, and a - output terminal 10 connects with a - input terminal 7 through a shunt 11. On the other hand, a dividing circuit is constituted by serial connection of a dividing thyristor protective coil 8 and a dividing thyristor 9, and the cathode side of the thyristor 9 is connected to the -output terminal 10, while the protective side is connected to the + output terminal 10. When currents begin to flow by the voltage signal of the magnetizer which is input through the shunt 11 to which a gate pulse generating control board 12 is connected, the points, where the maximum value and counter-electromotive fourth occur, are detected and respective lapse times are measured, and the time when the temperature rise of the coil is the smallest is set to pulses.