To easily grasp the scrolling direction, speed and locus respectively in a scroll mode by moving a reference point where the scrolling direction and distance are specified according to the scrolling direction and distance and also showing the moving locus of the reference point in a dotted line, etc.

The timer interruption processing of a prescribed cycle is started if a display (image) showing a locus does not exist (S11), a line is drawn to connect the coordinates (XP, YP) of a reference point to the relative positions XP-ΔX and YP-ΔY before movement of the coordinates (S12). If it is decided that an image showing a locus is already drawn, the image is shifted according to the scroll value (ΔX, ΔY) (S13). Then an image is drawn to connect the edge of the image showing the locus to the reference point (S14). The display (line) that is drawn in such a way shows a position where the reference point of a scrolling image passed as a dotted line.