An electric working apparatus includes a movable body which is driven by a movement mechanism, and the movable body is provided with a working mechanism such as an articulated robot. The movement mechanism, the working mechanism and etc. are driven by an electric power which is supplied through a power supply cord being extended from a cord reel mechanism fixed on a wall or floor within a working space of the movable body to be connected to the movable body. When the movable body moves in a manner that the movable body goes away from the cord reel mechanism, a tension detection switch is turned-off by a lever, a reel motor is turned-off, and clutch plates are released, and therefore, the power supply cord is wound from the cord reel mechanism by necessary length. When the movable body moves in a manner that the movable body approaches to the cord reel mechanism, the tension detection switch is turned-on by the lever and the clutch plates are engaged to each other, and therefore, the cord reel is rotated by the reel motor to wind the power supply cord.