Multiple video game apparatuses are connected to a game server apparatus. This network game progresses when players of the respective video game apparatuses exchange messages via the game server apparatus. When a predetermined event is generated by processing in the game server apparatus, a specific message is transmitted to each video game apparatus. In a chat window provided on a display screen of each video game apparatus, the message sent from the game server apparatus is scrolled and displayed from the bottom to the top. When the specific message reaches an uppermost portion of the chat window, a lock window is set and the specific message is displayed therein. The specific message in the lock window is not erased by the reception of a next message.