An A/D conversion circuit including a plurality of resistor elements connected in series between a low-potential power supply and a high-potential power supply. The A/D conversion circuit includes a plurality of comparators that compare a reference voltage divided by each of the resistor elements with an analog input voltage, the comparators having a sample-and-hold function for holding a sampled analog input voltage. The plurality of comparators also include a high-order bit comparator and a low-order bit comparator having different sampling sources. The high-order bit comparator may be configured to compare the analog input voltage and one of the reference voltages to obtain a determination result. The low-order bit comparator may old the analog voltage from the time that the low-order bit comparator retrieves the analog input voltage until the low-order bit comparator performs comparison.