A semiconductor device includes: an A/D converter; a digital processing circuit for performing processing based on conversion results from the A/D converter; a first test circuit for performing operation processing for checking a nonlinearity error (INLE) of the conversion results from the A/D converter; and a second test circuit for performing operation processing for checking a differential nonlinearity error (DNLE) of the conversion results from the A/D converter. The first test circuit performs only part of the operation processing for checking the nonlinearity error (INLE) of the conversion results from the A/D converter. The second test circuit performs only part of the operation processing for checking the differential nonlinearity error (DNLE) of the conversion results from the A/D converter. An operation processing section for performing the rest of the operation processing for checking the nonlinearity error (INLE) and the rest of the operation processing for checking the differential nonlinearity error (DNLE) is in a semiconductor test device.