A pulsed light generating method for generating a pulsed light by cutting out a laser light outputted from a laser light source with an intensity modulation type electro optic modulator, wherein: the electro optic modulator is driven by use of a drive signal that changes a voltage applied to the electro optic modulator between a voltage lower than a reference voltage and a voltage higher than the reference voltage, the reference voltage being a voltage applied to the electro optic modulator at which a transmittance of the laser light transmitting through the electro optic modulator is local maximum.