A regulating device includes: a generating means for generating an output voltage from an input voltage; a plurality of first switches, respectively corresponding to the plural storage battery units connected in parallel, with each of said first switches interposed between the corresponding storage battery unit and the input side of the generating means; a plurality of second switches, respectively corresponding to the plural storage battery units, with each of said second switches interposed between the corresponding storage battery unit and the output side of the generating means; a detecting means for detecting the voltage of each of the plural storage battery units; and, a control means that, referring to the result of detection from the detecting means, identifies first storage battery units whose voltages are higher than the average value of voltage of the plural storage battery units and second storage battery units whose voltages are lower than the average value, from the plural storage battery units, and turns on the first control switches corresponding to the first storage battery units from among the plural first switches and the second control switches corresponding to the second storage battery units from among the second switches.