To reduce standby time during charging, a charging device includes a housing on which a battery pack is detachably mountable, a control board, and a cooling fan. The battery pack is formed with a vent hole. The housing is formed with a ventilation opening configured to face the vent hole. The cooling fan is configured to flow an air passing through the control board and the ventilation opening, and is configured to work even in a state where the battery pack is detached.