A flash analog-to-digital converter having precise differential voltage interpolation without the use of silicide-blocked resistors. A reference conversion voltage output portion converts an analog input voltage on the basis of a plurality of reference voltages into a plurality of reference conversion voltages. An intermediate voltage generating portion includes a predetermined number of non-linear resistance units respectively provided between one voltage and the other voltage in pairs of a predetermined number of the plurality of reference conversion voltages to generate a plurality of intermediate voltages by resistance division using the predetermined number of non-linear resistance units. In addition, the intermediate voltage generating portion generates a plurality of conversion voltages. A digital data output portion outputs the digital output voltage on the basis of the plurality of conversion voltages using double interpolation. Each of the predetermined number of non-linear resistance units includes a first input terminal connected to the one voltage, a second input terminal connected to the other voltage, and a plurality of non-linear resistor elements having the same resistance value connected in series between the first and second input terminals. The plurality of intermediate voltages includes at least part of voltages obtained from one end of each of the plurality of non-linear resistor elements.