PURPOSE: To accurately perform continuous measurement, by performing the change-over between a plurality of rows of counters at an accurate time interval and drawing up measured data obtained by this so as not to generate a non- sensitive time.

CONSTITUTION: In a discrete pulse count circuit, two systems of counters A, B are prepared and, when the counter A performs counting, the counter B performs operation other than counting and, when the counter A does not perform counting, the counter B performs counting. This change-over is performed by changing over first and second change-over devices 12, 13 on the basis of a change-over clock signal Sc through a clock circuit 18 and an I/O port 19 and a count value is transmitted to an electronic control apparatus 15 at an accurate time interval to continuously store the count data rows from the counters A, B in a memory 17 in time series. Since the obtained measured data can be drawn up so as not to generate a non-sensitive time, there is no counter omission and accurate counting can be performed.