The voltage-controlled variable-frequency pulse oscillator in accordance with the present invention comprises an integrating capacitor, a variable current source for generating charging current for said integrating capacitor in response to the controlling voltage, a fixed current source for discharging said capacitor, a switching circuit for controlling the discharge of said capacitor, a comparator for outputting a discrimination signal by comparing the voltage of the capacitor and a reference voltage, and a multivibrator for receiving the discrimination signal from the comparator and for outputting a pulse signal with a frequency corresponding to the controlling voltage from the variable current source. The multivibrator comprises an R-S flip-flop for receiving the discrimination signal output by the comparator at its set side OR-NOR gates, and receiving and inverting the output of the reset side gate which is delayed by a prescribed time to the reset side OR-NOR gate. The R-S flip-flop is constructed to permit the oscillation output with a prescribed frequency to be taken out from the reset side OR-NOR gates, and the oscillation output of the R-S flip-flop controls the drive of the switching circuit. Therefore, the multivibrator starts oscillation on its own with a prescribed width when the capacitor voltage grows very large at the time of turning the power supply on or at the time of generation of an excessively large current where the output of the comparator continues to stay at a constant value. Furthermore, the current value of the fixed current source is set at more than twice the maximum current value of the variable current source. Because of this, the large voltage of the capacitor decreases gradually with ups and downs, and the comparator inverts after a certain time, the multivibrator discontinues the self oscillation, and the ordinary operation of the device takes place.