When a gate control device passes a current into a gate of a first thyristor while a DC power supply is in an on state, conduction of the first thyristor starts, and a current starts to flow through a coil ring. The flowing current is stored as a charge in a capacitor, and a flow of the current stops when a voltage generated by the charge stored in the capacitor becomes equal to a voltage applied by the DC power supply, so that a pulsed current flows through the coil ring once. A pulse width of the pulsed current is 0.5 msec or more and 5.0 msec or less. The pulsed current is passed through the coil ring at a relatively low frequency of 30 Hz or less. When the pulsed current flows through the coil ring, a pulsed magnetic field is generated. When the pulsed magnetic field is provided from the coil ring to body tissue of the human body, an electromotive force having a similar waveform to an action potential is generated in the body tissue.
