An image display apparatus is caused to display a life point meter for showing a total remaining life point within a life point display region on an image display screen. When an action or event occurs to any player character so that the remaining life point thereof changes, an amount of change of a life point thereof is calculated in response to the action or the event. It is determined that the battle possible state of all player characters can be maintained except that the amount of decrease of the life point is the total remaining life point or more. In the case where the remaining life point of the corresponding player character is updated on the basis of the calculated amount of change of the life point, the image display apparatus is caused to change a display form of the life point meter assigned to the corresponding player character.