PURPOSE: To expedite the response speed of IC, in the IC provided with a plurality of charge storing parts wherein the charge from a diffused layer are injected on a semiconductor substrate, charge transfer gates which transfer the charges therefrom, and a means to detect said charge, by arbitrarily selecting the storing parts by the gates.

CONSTITUTION: One side of each of a plurality of the charge storing parts 1∼4 having different areas are connected to a floating junction 43 through the charge transfer gates 11∼14, and the other sides are connected to charge injecting diffused layers 31∼34 via input gates 21∼24. Then the gates 11∼14 are branched and connected to a decoder 42 having inputs 41. The floating junction 43 is connected to a reset ransistor 46 having a reset gage 44 and a reset power source 45, and also to an output transistor 48 having a power source 47 and an output 50. An output transistor 49 is connected to the transistor 48. In this constitution, the transfer gates and the storing parts are arbitrarily combined, and the selcted charge is transferred.