A charging device of a robotic lawn mower includes a bottom part installed in a partial region of an operation region of the robot, a support part coupled to the bottom part and positioned on a side of a main body of the robot when the robot is being charged, and a terminal part coupled to the support part and positioned above the main body of the robot when the robot is being charged, wherein the bottom part is formed such that only any one of a plurality of wheels of the robot is mounted thereon when the robot is being charged.