A charger configured to charge batteries includes a housing including a plurality of battery storage chambers accommodating the batteries, the battery storage chambers being aligned in a horizontal direction such that depth directions of the battery storage chambers are parallel to each other; openings formed on first ends of the battery chambers in the depth direction, the batteries being attached to and detached from the battery storage chambers through the openings; and charger-side terminals provided on the battery storage chambers, the charger-side terminals being connect to and disconnect from battery-side terminals of the batteries stored in the battery storage chambers.