To prevent tearing in displaying images landscape images having a long aspect ratio in a landscape direction by using a display screen for displaying portrait images having a long aspect ratio in a portrait direction.

When data read reaches an R/2 line which is a half of the total lines R to be read on a RAM 5, as shown in (2a), a display device sequentially writes image data PC to the lines 1 to R/2 in a storage region of the RAM 5. In the same way, when the data read reaches the total lines R to be read on the RAM 5, as shown in (3a), the display device sequentially writes the image data PC to the lines R/2+1 to R on the RAM 5.