This invention relates to a battery structure with improved safety. The battery structure includes: at least two batteries disposed axially parallel to each other, positive terminals thereof facing opposite directions, negative terminals thereof facing opposite directions; an insulating material covering each of the batteries; and a connecting member provided at an end of the at least two batteries for connecting the positive terminal of one of the batteries with the negative terminal of the other battery. The connecting member includes: a negative terminal connector attached to the other battery so as to come into contact with the negative terminal of the other battery; and a bus bar connected at one end portion thereof to the positive terminal of the one battery. The negative terminal connector has a socket into which the other end portion of the bus bar is to be inserted. The tip of the other end portion of the bus bar in the direction of insertion into the socket is chamfered so that it does not impair the insulating material.