A game system includes a plurality of game apparatus that can carry out short-range wireless communication with one another. One of the game apparatus functions as a parent apparatus, and at least one other game apparatus functions as a child apparatus. The parent apparatus transmits transmission verification data a predetermined number of times. Accordingly, the child apparatus receives the transmission verification data from the parent apparatus, and transmits to the parent apparatus the same number of piece(s) of reception verification data as those of the received transmission verification data. The parent apparatus receives the reception verification data from the child apparatus, and detects the number of the received piece(s) of reception verification data. Also, the parent apparatus varies a game process according to the number of the received piece(s) of data detected in communication with each child apparatus, and, for example, decides a communication priority rank of each child character based on the number of the received piece(s) of data. In addition, the child apparatus varies a game process according to the number of the received piece(s) of data corresponding to this apparatus itself.