Abstract: A power supply system includes a plurality of power supply devices which are mounted in a mount region and a control [means] unit (namely, a central processing unit), The control [means] unit is connected to the power supply devices and sets a power supply quantity to be supplied to an external load apparatus. [Herein,] The power supply devices are assigned connection positions as addresses in the mount region[, respectively]. Further, the power supply devices send the connection positions as connection position signals into the control [means] unit. The control means determines the number of the power supply devices based upon the connection position signals and sets the power supply quantity based upon the number.