The value relating to the average of the length of processing time required to process a plurality of information sets is reduced. The information processing device comprises: a receiving component receiving information elements contained in respective information sets having one or more information elements, from one or a plurality of information set sources issuing the information sets; an information processing component carrying out processing of the information elements thus received; and a determining component determining a processing sequence for the two or more information sets or the plurality of information elements, on the basis of the plurality of information elements that are unprocessed or currently being processed, contained in two or more information sets thus received, and determining a processing sequence different from the reception sequence, in which a value relating to the average of the length of processing time for the two or more information sets becomes equal to or less than the value that would be obtained were the plurality of information elements or the two or more information sets to be processed in accordance with their reception sequence; the processing of a plurality of information elements that are unprocessed or currently being processed, being started on the basis of the processing sequence thus determined.