PURPOSE: To stabilize a holding function of a memory by charging a secondary battery of the memory with electricity by using charging electric power supply converted from control electric power supply when a control electric power- supplied robot system is operated and by using charging electric power supply converted from a vehicle battery when the control electric power supply to the robot system is stopped.

CONSTITUTION: Two systems are formed for charging of a secondary battery 4 for a memory. That is, the first system converts vehicle battery electric power supply 7 outputted from a vehicle battery 1 into vehicle battery system charging electric power supply 8 through a DC/DC converter 2, and inputs it to a switching unit 3. The second system converts control electric power supply 10 generated by a generator 5 to be supplied to a control device when a robot system is operated into control electric power supply system charging electric power supply 11 by an AD/DC converter 6, and inputs it to the switching unit 3. When a switching observing unit 12 judges that supply of the control electric power supply system charging electric power supply 11 does not exist, the switching unit 3 switches the system so that the first system is used.