PURPOSE: To provide the sequential sampling system which stabilizes the sampling operation.

CONSTITUTION: A reference signal generation means 1 which outputs a reference signal 1a having a frequency fr, a measurement object signal generation means 2 which outputs a signal 2a for measurement whose frequency is L times (L is an integer larger than one) as high as the frequency fr, a sampling signal generation means 5 which outputs a sampling signal 5a which is synchronized with the reference signal 1a and has the frequency expressed by fr×L×{N /(M×N+1)} where M and N are integers larger than 0 and M is the number of periods of the signal 2a for measurement required for one sampling and N is the number of sampling points in one period of the signal 2a for measurement, and a sampling means 4 which samples a signal 3a to be measured, which is obtained by inputting the signal 2a for measurement to an object 3 to be measured, by the sampling signal 5a are provided, and M and N are so set that ×N+1=2X×5Y (X and Y are integers larger than 0) is true.