Apparatus and method for switch control, and voltage measuring device

A voltage-measuring device includes a capacitor for being connected sequentially to each of a plurality of unit cells connected in series to each other composing a battery pack. Further, the voltage-measuring device includes a plurality of switches for connecting sequentially the unit cells to the capacitor. The capacitor is charged by one of the unit cells, and reflects a voltage of the one of the unit cells. A logic circuit firstly turns one of two switches provided between the capacitor and a voltmeter, and then secondly turns the other switch on for connecting the voltmeter to the capacitor. The voltmeter measures a voltage across the capacitor when the other switch of the two switches is secondly turned on.