An A/D conversion integrated circuit including a plurality of A/D converters which can inhibit noises from being propagated by capacitive coupling from a conductor which transmits a digital signal is provided. In an A/D converter 13, an input 15 receives an analog signal to be A/D converted. An output 17 provides at least a part of a digital signal SD having a predetermined number of bits representing the analog signal SA. In response to an analog signal SA, a sub-A/D conversion circuit 19 generates a signal SDP representing one or a plurality of bit values of the digital signal SD and feeds the signal SDP to the output 17. An input 21 a of a control circuit 21 is connected to an output 19a of the sub-A/D conversion circuit 19 and provides a control signal SCONT corresponding to the signal SDP. The control signal SCONT has a waveform including a transition from a voltage level L1 to a voltage level L2 and a transition from the voltage level L2 to the voltage level L1.