A power amplifier includes: a modulator pulse-modulating a drive waveform signal serving as a reference of a drive signal applied to actuators and outputting a modulated signal; a digital power amplifier amplifying the power of the modulated signal and outputting an amplified digital signal; a low pass filter smoothing the amplified digital signal and outputting the drive signal; and an inverse filter circuit being disposed at a front stage of the modulator and capable of obtaining a desired waveform precision of the drive signal even when a frequency characteristic of a filter including the low pass filter and an electrostatic capacitor of the actuators varies depending on the number of driven actuators, wherein the inverse filter circuits include a plurality of inverse filters connected in series.