A signal measuring device, comprises one set, or a plurality of sets, of measuring unit(s) measuring an object of measurement in synch with a driving clock signal for measurement and outputting result of measurement as first data, and a timing identification unit which, in accordance with a measurement-start command, outputs a value, which differs every period, as second data in synch with a reference signal having a prescribed period and a speed lower than that of the driving clock signal; and a storage unit collecting and successively storing the first data and the second data as one set in synch with the driving clock signal.