A charging device includes: a connection portion; charging means; and control means. A first type battery pack and a second type battery pack are connectable to the connection portion. The first type battery pack is configured to control charging itself to determine whether charging is feasible. The second type battery pack is configured to provide information to the charging device for determining whether charging is feasible and controlling a charging operation. The charging means supplies charging current to a secondary battery included in a battery pack connected to the connection portion. The control means is configured to control a charging condition based on a type of the battery pack connected to the connection portion.