PURPOSE: To provide the time-division multiplying device which can prevent a measurement error from being generated owing to variation in voltage level when plural voltage levels are brought under ON/OFF control and inputted to one multiplier, and then multiplied alternately.

CONSTITUTION: When the voltage levels are brought under ON/OFF control and inputted to one operational amplifier 10 (multiplier), and then multiplied alternately, a specific time which is longer than one multiplication period of the operational amplifier 10 is determined by a timer circuit 130, and a flip-flop 51 detects a non-multiplication period from the determined specific time and one multiplication period. In the non-multiplication period, all the voltage levels are inhibited by analog switches 61 and 62 from being inputted.