A charger (5) includes connecting parts (31, 32), a main converter (83), charging paths (Cpa, Cpb), switching elements (SWa, SWb), and a charging-control part (200). A first battery (Ba) having a first mounting part (11) and a second battery (Bb) having a second, different mounting part (21) are respectively mountable on the connecting parts (31, 32). The charging paths (Cpa, Cpb) respectively connect the main converter (83) to the connecting parts (31, 32). The switching elements (SWa, SWb) respectively connect or disconnect the charging paths (Cpa, Cpb) to/from the main converter (83). The charging-control part (200) selects one of the batteries (Ba, Bb) as the charging target and sets the charging path, to which the charging target (Ba, Bb) is connected, to the connected state. Then, the charger (5) charges the charging target to a predetermined voltage using a charging current suited to the charging target.