Various circuit technologies have been studied and developed. One of main streams concerns a soft switching technology to mitigate switching stress, leading to the reduction in switching losses or electro-magnetic noise. On the other hand, as a characterized orthodox technology, the existing chopper circuit is used for the electric vehicles, etc. Such technologies have a tendency to go out of vogue as power supplies for such vehicles. However, as a boost chopper for the battery charger for an electric vehicle, those technologies become a main stream, where a bilateral function is required. With the foregoing in mind, the authors have devised and analyzed the bilateral chopper using the soft-switch technology, which could be applied to a battery charger for an electric vehicle or similar.