User's error operation is prevented by effectively distinguishing an inputting operation of specifying an area on a display screen from a touching or click inputting operation of specifying one point and an operation of sliding an input of one point while continuing inputting the point. The present invention determines a coordinate of a first intermediate point calculated from coordinates of first two points based on the coordinates of the first two points simultaneously inputted to a coordinate input unit, and determines a coordinate of a second intermediate point calculated from coordinates of last two points based on the coordinates of the last two points detected immediately before the coordinates of the two points stop being simultaneously inputted. Further, the present invention defines an area on a display screen of a display unit based on the coordinate of the first intermediate point and the coordinate of the second intermediate point.