Three user characters are displayed in a chat room. When a user inputs a character string, the character string is displayed on the screens of the respective users. When a character string inputted by a user contains a character string "Ha,Ha,Ha", a data table outputs an event corresponding to the character string "Ha,Ha,Ha". All the user characters participating in the chat make a laughing action, uttering the laughing sound "Ha,Ha,Ha". The input character processing method not only can simply transmits utterances of respective participants but also can occur various events.