a switching unit including a first electrode having a conductive beam and second and third electrodes disposed on both sides of the conductive beam and attracting the conductive beam by electrostatic force, based on an operating voltage applied between the second and third electrodes and the conductive beam, the conductive beam, after being attracted by and adhered to the second or third electrode, maintained to be adhered even when the electrostatic force is removed; and

a controller determining an operation mode according to types of logic operations included in input data, setting an initial position of the conductive beam by applying the operating voltage to any one of the second and third electrodes according to the determined operation mode, selecting at least one of the first to third electrodes according to the determined operation mode, and applying a predetermined voltage as a true value of a logic value included in the input data.