PURPOSE: To make held data unvaried and to enable use directly held data at the time of turning on power supply by converting an input data to digital data and storing it in a memory element, while outputting it through a latch circuit and a D/A converter circuit.

CONSTITUTION: An input voltage data Vi from an input buffer circuit B1 is stored in a memory element 3 through a switch S1, a D/A converter 1, while outputted through a latch circuit 2a, an A/D converter 2, and an output buffer circuit B2. By this constitution using no capacitor in which held voltage data is varied as time elapses, a sample-and-hold circuit in which held voltage data is not varied and held voltage data can be directly taken out even when power supply is turned on is obtained.