Print log information representing an output sheet count in each of a plurality of image forming devices is acquired. Next, print log information of output products is acquired for each department or user capable of using the image forming device. Then, total print log information representing the output sheet count of the plurality of image forming devices is acquired. When the sum of output sheet counts specified by the print log information acquired first coincides with the sum of output sheet counts specified by the total print log information, the print log information or total print log information acquired for the department or user is decided as the sum of output sheet counts of the department or user.