the battery holding method and structure enable contact points between a battery and terminals to be maintained invariant in location by improving a performance in holding the battery , and accordingly a stable contact resistance can be obtained . a battery holder forms a battery chamber , and the battery chamber makes a space for housing a battery inserted along a lengthwise direction thereof . the battery holder is equipped , on a side surface thereof , with a nail for pressing the battery in touch with the side surface of the battery . when the battery is inserted into the battery chamber , the nail is deformed elastically , and the resulting restoring force thereof fixes the battery in a definite arrangement in the battery chamber with a slight and eccentric displacement . possible modes include a mode in which a link lever is used for pressing the side surface of the battery in conjunction with the battery insertion operation , and a mode in which is used a mechanism wherein a pressing member is made to take a releasing position or a locking position in conjunction with opening and closing operations of a battery chamber cap .