PURPOSE: To prevent an image from deteriorating in picture quality when displayed on an image display device even if error data is generated owing to a fault on the image storage device when data are read sequentially out of an image storage device stored with two-dimensional image data.

CONSTITUTION: An erroneous data detection part 21 detects the erroneous data of the two-dimensional image data sequentially out of the image storage device 1 and an erroneous data counting part 22 counts successive frequency of erroneous data in an X and a Y direction and their positions. A data skip and takeout part 23 skip the erroneous data and takes specific excellent data adjacent to the erroneous data out on the basis of the counting information, and an interpolation part 25 interpolates the erroneous data part with the excellent data. Consequently, when image data are displayed on a CRT 33, the picture quality is prevented from deteriorating.