To provide an oscillation circuit which can stably obtain a pulse oscillation signal with a large duty ratio by a capacitor having irreducible minimum capacity as an oscillation circuit which outputs a pulse oscillation signal with a large duty ratio.

The oscillation circuit which charges and discharges the capacitor C11 and inverts the output according to the voltage of the capacitor C11 to generate an output oscillation pulse signal is provided with a discharging accelerating circuit 12 consisting of an NPN transistor(TR) QT7 which is actuated when the capacitor C11 is discharged and detects the voltage across the capacitor C11 and NPN TRs QT7 and QT8 which turn on by a decrease in the emitter current of the NPN TR QT7 and accelerate the discharging of the capacitor C11.