An analog-to-digital conversion device which converts an analog input signal into a digital signal and output it includes a signal characteristic detection unit for detecting a predetermined characteristic of the input signal; a control signal generation unit for setting a resolution based on the signal characteristic detected by the signal characteristic detection unit, generating a control signal that indicates only an operation required for performing the analog-to-digital conversion at the resolution, and outputting it; and an analog-to-digital conversion unit for restricting the operation based on the control signal and converting the input signal into the digital signal at the set resolution.