In order to provide a signal measuring apparatus which satisfies multiple performances at a high level all together, the signal measuring apparatus includes: DC performance; noise performance; distortion performance; spurious performance; and the like, a signal measuring apparatus includes: multiple A/D converters which respectively have different conversion characteristics for converting from an analog signal outputted from a DUT to digital signals; digital circuits which are provided in correspondence with the A/D converters and which conduct predetermined operations based on the conversion characteristics of the A/D converters.