To increase the speed of writing processing speed for a recording area where data with predetermined contents are written in the predetermined order of addresses, as in TOC areas, on a recording medium, such as a flash memory.

The proper address position in a predetermined memory area where each group of data should be written is converted into a converted address position where data are arranged in the order of addresses in the memory area, in response to writing instructions for each group of data, whereby each group of data is written in sequence in the predetermined memory area. Information showing the correspondence between the proper address position and the converted address position is retained for reading each group of data.