To solve the problem that the measurement of jitters has been effective to adjust a digital signal device and evaluate a signal recording medium, however, an expensive special purpose measuring instrument has conventionally been necessary for measuring jitters.

In the recording waveform measuring instrument, the edge of a recording waveform read from a digital signal recording medium is detected, the time from the edge detection up to the next edge detection is measured for every one edge period, the measured times are successively stored in memory 14 as data, the data stored in the memory 14 is outputted to a host equipment 5 via an interface 9, the data are classified for every inversion period of the recording waveform of the digital signal recording medium by the host equipment 5, and the measurement results are displayed for every inversion period of the classified recording waveform. In such a manner, the configuration is simplified by dividing responsibility between the digital signal device and the host equipment 5.