To provide a grouping technology of entrants capable of disturbing continual succession of an act for fraudulently advantageous progress of a competition by an ill-intentioned entrant with nobody noticing when deciding the grouping of the entrants in the competition executed via a communication line.

A server device 10 records an entrant who has won in the competition executed in a same group into a database device 11 about each the entrant, inquires of the database device 11 when executing the grouping thereafter, and executes the grouping such that each the entrant does not belong to the same group as the entrant who has won against himself in the past, as far as possible.