PURPOSE: To eliminate the need for a scroll starting operation by users and to obtain optimum scroll speeds while matching with the individual characteristics and utilization conditions of the users.

CONSTITUTION: When a predetermined window is opened, a scroll speed arithmetic part 3 inputs data on the number (x) of characters in one line and window width (w) from a window are specification part 4 and also inputs a user basic scroll speed function S(x) from a user basic scroll speed setting part 1 and a basic scroll speed storage part 2 to calculate a user basic scroll speed S(x). A window display part 6 regards this arithmetic value as an initial speed to perform the automatic scrolling operation in a specific direction. When a temporary variation value β is supplied from a scrolling operation designating part 5 in the middle of the automatic scrolling operation, the scroll speed arithmetic part 3 calculates a scroll speed S(x) again and the current scroll speed is varied to the speed of the arithmetic value.