To safely control irregular pulses by generating the stimulation having the polarity opposite to that of the electric stimulation extending the refractory period, applying this stimulation after the stimulation extending the refractory period, and keeping the sum of the charge quantity of the stimulation neutral.

This stimulation output circuit is constituted of a transistor Tr1, a resistor R, and a capacitor C, a transistor Tr2 is additionally connected in parallel with the resistor R of this circuit, and the circuit is controlled by a control signal 9 to generate a reverse-polarity pulse. In this circuit, the current from an electrode +V normally flows through the resistor R, the capacitor C, and the cardiac muscle connected to an output terminal. The capacitor C is gradually charged. When the transistor Tr1 conducts, a stimulative pulse is generated by the discharge of the capacitor C. When the transistor Tr2 conducts, the capacitor C is quickly charged, and a reverse-polarity pulse is generated. The cardiac muscle potential is made neutral, and the occurrence of very dangerous fibrillation is prevented.