A light emitting diode driving circuit for supplying a driving pulse to a light emitting diode to thereby cause the light emitting diode to intermittently emit light is disclosed which comprises a clamping circuit, a photodiode disposed in the vicinity of the light emitting diode for detecting the optical output power of the light emitting diode, an AC amplifier having its DC operating point stabilized by means of a DC feedback circuit for AC amplifying the detected output from the photodiode, a shaping circuit for shaping the output amplified signal from the AC amplifier, and a comparison circuit for comparing for voltage the output shaped signal from the shaping circuit and a reference voltage, in which the clamping voltage of the clamping circuit is controlled by the output of the comparison circuit and, thereby, the optical output power of the light emitting diode is maintained constant.