A laser diode driving circuit includes two chip capacitors disposed in the vicinity of one side portion of an IC along which a high voltage power supply terminal, a low voltage power supply terminal and a driving signal output terminal are disposed. One end portion of each of the chip capacitors is connected to the high voltage power supply terminal and the other end portion of each of the chip capacitors is connected to the low voltage power supply terminal. The chip capacitors are adapted for serving to reduce a ripple component superposed on a power supply voltage when a switching element is operated. The chip capacitors are disposed so that the distance between itself and the high voltage power supply terminal, the low voltage power supply terminal and the driving signal output terminal is equal to or shorter than 10 mm.According to the thus constituted laser diode driving circuit, it is possible to generate a good driving signal even when the pulse width of pulsed light emitted from a laser diode is narrow.