Charging system for legged walking robot

An inexpensive charging system with a simple construction can supply charging current to a battery of a legged walking robot while maintaining the supply of required current to an electric load of the legged walking robot by an external power source. The charging system includes a connection circuit having a first, a second diode, a third diode, and a circuit that brings various negative electrode and a negative input terminal of the electric load into conduction, and an output electric power controller that sets an output voltage of the external power source to be higher than a total voltage of a voltage across electrodes of the battery when the battery is fully charged and a forward voltage of the third diode, while setting a current of the external power source that can be output to be larger than a required current of the electric load.