An A/D converter includes a delta-sigma processing circuit for A/D conversion by delta-sigma modulation, and a cyclic processing circuit for A/D conversion by cyclic processing of amplification of a residue generated in the A/D conversion. The A/D converter further includes a quantization part for outputting a quantized value of quantized output of the delta-sigma processing circuit and a quantized output of the cyclic processing circuit, and a control circuit for generating an A/D conversion result and switching over a reference voltage based on the quantized value. The delta-sigma processing circuit and the cyclic processing circuit include a sampling capacitor, an integration capacitor and a capacitive D/A converter, which includes a DAC capacitor and add and subtract a charge corresponding to a reference voltage to and from a residue of quantization. The sampling capacitor, the DAC capacitor and the integration capacitor are provided as electrically separate capacitors.