In writing image data having a first size in a memory card (4), a DMA circuit (12) transfers the image data to a memory card controller (6) until the write of the image data having the first size is ended. The memory card controller (6) checks that the state of the memory card is a predetermined state every time the write of image data having a second size smaller than the first size in the memory card (4) is ended and outputs a transfer end interrupt request signal to a CPU (2) in accordance with the end of the write of the image data having the first size in the memory card.