A charging apparatus used with a mobile robot has an improved charging structure so that a mobile robot is easily brought into electrical contact with a charging unit, thereby reducing manufacturing costs and preventing a charging failure. The charging unit is provided with a plurality of charging terminals which are brought into electrical contact with corresponding ones of contact terminals of the mobile robot. Each of the charging terminals includes a body and a head. A contact plate is mounted to a predetermined portion of the head to be brought into electrical contact with a corresponding one of the contact terminals.