It is possible to reduce a noise component mixed in an analog signal while suppressing increase of power consumption. An amplification unit amplifies the inputted analog signal and converts the amplified signal into a digital signal of a predetermined format for output. The amplification unit includes: an analog circuit unit for processing an analog signal; and a digital circuit unit for processing a digital signal; wherein the circuits are arranged on a substrate. The analog circuit unit includes: an amplification circuit for amplifying the inputted analog signal; and an LPF for cutting off a high frequency component of the amplified analog signal. The digital circuit unit includes: a rectification circuit which rectifies a waveform of the signal whose high-frequency component is cut off; and digital output circuit which converts the waveform-rectified signal into a digital signal of a predetermined format for output.