modulator 9 through the drive transistor 4 and the signal switching section 40 a 1 bit digital modulated signal produced here is outputted into the simplified tester 91 from the delta sigma modulation output terminal 2 the simplified tester 91 can receive a 1 bit digital modulated signal outputted from the delta sigma modulation output terminal 2 through the probe card 92 the simplified tester 91 displays a pulse waveform of the 1 bit digital modulated signal inputted from the delta sigma modulation output terminal 2 through the probe card 92 so as to be observed on a display unit moreover digital signal processing such as demodulation processing is applied to the pulse waveform to measure the demodulated digital voltage value at this time if the measured voltage value is deviated from a voltage value to be outputted a voltage value of a test pattern by at least a predetermined value if correction is not sufficiently performed by correction data the drive device 53 is determined as an inferior component when it is within a correctable range even if the measured voltage value deviates the drive device 53 is determined to be usable the delta sigma modulator 9 itself may have some malfunction however a delta sigma modulated signal is not outputted or a waveform pulse abnormally goes wrong so observation of such states indicates whether or not the drive device 53 should be handled as an inferior component an example illustrated in fig6 can make a check and evaluation with the probe card 92 having needles of a very small amount per drive lsi 10 needles in.