Interconnection structure between portable telephone and battery pack

In a battery pack, pitfalls are provided at both end portions in the width direction of a rear surface lower portion of a portable phone main body. Projections higher than the electrode pins are provided at both ends in the width direction of a lower surface lower end portion of the battery pack at the position corresponding to the pitfalls. Grooves or a gap for guiding the projections are provided at both end portions in the width direction of the rear surface of the portable phone main body. In mounting the battery pack in the portable phone, the projections are contacted with the rear surface of the portable phone so that the battery pack slides to the lower side of the portable phone main body with the projections guided along the grooves gap. When the projections drop in the pitfalls after the tip of the battery pack passes above the pins, the pins are forced against the electrode of the battery pack according to the force of a biasing spring so as to be connected electrically in a conventional manner. The battery pack is fixed in position by fitting the upper end of the battery pack with a battery engaging portion of the portable phone.