An analog-to-digital conversion device and analog-to-digital conversion method thereof are provided. The analog-to-digital conversion device includes an analog circuit configured to output an analog input signal, and an analog-to-digital converter configured to receive the analog input signal and configured to outputting a digital output signal corresponding to the analog input signal with the use of first and second capacitor arrays, each of the first and second capacitor arrays including a first capacitor having a calibration capacitor connected thereto and a second capacitor having no calibration capacitor connected thereto, wherein the analog-to-digital converter is configured to calibrate the capacitance of the first capacitor by providing a first calibration voltage to the calibration capacitor and is configured to output the digital output signal corresponding to the analog input signal with the use of the calibrated capacitance of the first capacitor.