The type of the attached batteries is determined by decision switch mechanisms. A protruding region is established in the attachment section to provide contact between charging terminals and the electrodes of short batteries. A stepped shelf region is established with the protruding region, and long batteries are mounted inside the attachment section on top of the stepped shelf region. Charging terminals are disposed in electrode alignment surface of the stepped shelf region, and decision switch mechanisms are housed inside the stepped shelf region. A decision switch mechanism is a switch that switches when pressed by the battery electrode of either a long battery or a short battery loaded in the attachment section. The control circuit switches charging current between a first charging current and a second charging current depending on the OFF or ON state of the decision switch mechanisms.