Abstract: A digital contents area displayed on a terminal is detected, and an area to be charged is calculated according to the detected area. A criterion for determining that a user reads the digital contents is a time during which the area of the contents is displayed. If the time is equal to or longer than a predetermined time, the displayed contents area is determined to be an area to be charged. There are two methods, a page-change button method and a scroll method, as a method that measures a contents display time for determining whether an area is to be charged.