An analog/digital converter includes: a first analog/digital conversion unit that performs digital conversion on received first analog input voltage in a first time period; a second analog/digital conversion unit that performs digital conversion on received second analog input voltage in a second time period that is different from the first time period; and a first coupling capacitor that connects the first analog/digital conversion unit and the second analog/digital conversion unit, and wherein the second analog/digital conversion unit receives, through the first coupling capacitor, first residual voltage that is remaining voltage of the first analog input voltage on which digital conversion is performed in the first analog/digital conversion unit, as the second analog input voltage.