To facilitate the discrimination between data read out by a magnetic card reader and data inputted by an external key board.

Bit data of the magnetic card 15 are read out by the magnetic card reading part 11. All of the read out bit data are stored in separate bit data storage parts 30 for every track. After that, each track is decoded in order by a data decode part 27, and the decoded data are stored in a decoded data storage part 31. At this time, starting codes of each track are replaced with header data, and ending codes are replaced with footer data.