A PWM signal generating apparatus configured to generate a PWM signal by applying parallel serial conversion to pattern data obtained by converting input data into a waveform pattern of a PWM signal having one pulse divided into a predetermined number of pulses, the PWM signal generating apparatus including: a clock generating circuit configured to generate a plurality of clock signals having mutually different phases; a conversion circuit configured to convert the input data into the waveform pattern of the PWM signal; an encoding circuit configured to generate, from the waveform pattern, a plurality of encoded signals synchronized with respective clocks of the plurality of clock signals generated by the clock generating circuit; and a decoding circuit configured to generate the PWM signal from the plurality of encoded signals output from the encoding circuit.