PURPOSE: To provide the frame memory constitution system for the display device which can reduce access for reading or writing display data.

CONSTITUTION: A frame memory part 2 has a display frame memory 2a for storing the display data and a modification frame memory 2b for storing modification data; and the display frame memory 2a is divided into a 1st display area 2a-1 and a 2nd display area 2a-2 and the modification frame memory 2b is divided into a 1st modification area 2b-1 and a 2nd modification area 2b-2. The 1st display area 2a-1 and 2nd modification area 2b-1 are connected to a bus 10a and the 2nd display area 2a-2 and 1st modification area 2a-2 are connected to a bus 10b; and a frame memory control part 4 reads the display data out of the 1st display area and the display data out of the 2nd display area at the same time and displays them one over the other at a display device 1.