Magnetic field generation device, method for controlling magnetic field generation device, and magnetic recording medium processing device

Provided are a magnetic field generation device, a method for controlling a magnetic field generation device, and a magnetic recording medium processing device, with which an interfering magnetic field can be generated continuously and efficiently. Specifically, the magnetic field generation device has: a magnetic field generation unit (51) that includes a resonance unit in which a coil (inductor) (L51) and a capacitor (C51) are connected, and that charges the capacitor and discharges the charge that has been charged, thereby causing an alternating current to flow between the inductor and the capacitor, and generating a magnetic field by means of resonance; a current direction monitoring circuit that monitors the direction of the current flowing in the inductor of the magnetic field generation unit (51); and a determination unit (523) that controls the timing for charging in the magnetic field generation unit in accordance with the direction of the current flowing in the inductor, as obtained by monitoring with the current direction monitoring circuit.