A semiconductor device according to the present invention has a capacitance DAC (Digital-to-Analog Converter) circuit and a comparator.The capacitance DAC circuit includes: first capacitors to which input signals are given and each of which has a capacitance value corresponding to a weight of a bit to be converted; and second capacitors to which common voltages are given and whose sum of capacitance values is equivalent to that of the first capacitors. Further, the second capacitors include: a redundant bit capacitor having a capacitance value corresponding to a weight of a redundant bit; and adjustment capacitors each having a capacitance value obtained by subtracting the capacitance value of the redundant bit capacitor from the sum of the capacitance values of the second capacitors.