A sampling circuit includes a latch circuit which latches the digital signal S1 at a constant period, an addition register which adds the sampled data for the same input code, a divider which divides the added value by a predetermined divisor, a digital memory which stores the divided value and outputs it at an arbitrary timing for a predetermined reading out number, an operator which operates the output data from the digital memory in accordance with a previously set algorithm, a judgment circuit which judges the operation result with a predetermined judgment criterion, and a control logic part which controls such that the addition and outputting processing by the addition register and the division and outputting processing by the divider are carried out concurrently with the sampling processing by the latch circuit. This sampling circuit in an AD converter or a DA converter can reduce inspection cost.