A charging system includes a control device (4) of an electrical treatment device and a charging device (6) that charges the control device (4) by contactless charging. The charging device (6) includes a support portion and a holding portion with a recessed shape formed in the support portion for fitting the control device (4) into. The control device (4) includes a light emission unit (406) that emits light when the control device (4) is fit in the holding portion. The charging device (6) includes a light reception unit (450) that receives light from the light emission unit (406), an authentication unit (452) that executes authentication processing in which first information based on light received and predetermined second information are compared； a transmitter coil (72) for transmitting power； and a power transmission control unit (456) that transmits power from the transmitter coil when authentication by the authentication unit is successful. The control device (4) includes a receiver coil (54) that receives power from the transmitter coil (72) and a rechargeable battery (240) chargeable by power received by the receiver coil (54).
