PURPOSE: To make it possible to utilize an external pattern for the display on a keyboard by registering the external pattern by the data when a registration on the memory card of a touch input keyboard for which a shift JIS code is used is performed.

CONSTITUTION: A computer system main body 1 has an external character code pattern file 2 where the external character codes and external character patterns expressed by JIS codes are registered. A touch input keyboard 3 has an external character registration control part 5, and this reads the external character pattern of an arbitrary section which is registered in the file 2 and registers it in a memory card 6. The keyboard 3 has a code conversion control part 4, and this converts the external character code inputted from the main body 1 from the JIS code to a shift JIS code and registers it in a memory card 6. Subsequently, the external character pattern registered in the memory card 6 is read and it can be utilized for a display by using the shift JIS code of the external character registered in the memory card 6 within the keyboard 3.