The present invention relates to a handheld radiotelephone having a battery pack attachably and detachably equipped on a rear surface of a main body, and a locking device for allowing the battery pack to be attached or detached. The locking device operates in a perpendicular direction with a length direction of the radiotelephone, and the battery pack is attached or detached while forming an arc around an end of the radiotelephone. The locking device includes an elastic locker having a predetermined elasticity, of which one end is fixed to a predetermined position of a lower casing frame of the radiotelephone and the other end is selectively locked in a locking hole. A pusher installed on the elastic locker, for pushing the elastic locker.