In an information processing system in which processing to be performed on a plurality of processed devices is shared and executed by a plurality of processing devices, load sharing is performed in units smaller than a processing request unit created. A request storing section of a main device stores a processing request including description of a plurality of devices to be processed which are processing objects and description of a processing content to be performed thereon. If the work load of an unexecuted processing request read out from the request storing section is heavy, a request dividing unit of each sub device divides the unexecuted processing request into a processing request including description of processed devices of the number commensurate with the processing by a processing unit and description of a processing content to be performed thereon, and a processing request including description of the remaining processed devices and description of a processing content to be performed thereon, and causes the processing unit to process the former processing request.