An electrical device includes a plurality of apparatus connected with a daisy chain connection through a communication line so that the apparatus communicate with each other through the communication line; and a control unit connected to one of the apparatus at an end stage thereof so that the control unit is configured to communicate with the one of the apparatus. The apparatus includes an address setting unit for setting a specific number to an address of the apparatus according to an address setting command when the apparatus receives address setting data including an address addition instruction as the address setting command for adding the specific number to the address of the apparatus. The apparatus further includes an address setting data transmission control unit for outputting the address setting data to a later stage apparatus when the address setting unit sets the specific value to the address of the apparatus.