An analog-to-digital conversion apparatus includes: a first analog-to-digital converter and a second analog-to-digital converter that are configured to convert an input analog signal into a digital signal; a difference imparting part configured to provide a difference of at least a fixed signal α between input analog signals to the first and second analog-to-digital converters, to input the input analog signals thereto; a first non-linear compensation part and a second non-linear compensation part that are configured to compensate non-linear distortions of a first output signal and a second output signal depending on the control variable signal to be supplied; and a non-linear detection part configured to estimate how much the non-linear distortions are compensated by the first and second non-linear compensation parts depending on a first signal by the first non-linear compensation part and a second signal by the second non-linear compensation part.