An analog converter includes an offset/gain value storage unit that is composed of a nonvolatile memory and stores therein offset/gain values, an operation unit that performs analog-digital conversion by using the offset/gain values in the offset/gain value storage unit as values for an interpolation operation, a previous offset/gain value storage unit that is composed of a nonvolatile memory and stores therein, as previous offset/gain values, the offset/gain values in the offset/gain value storage unit used in the past, wherein the operation unit includes an offset/gain value setting unit that controls setting of the offset/gain values in the offset/gain value storage unit and storage of the previous offset/gain values in the previous offset/gain value storage unit.