PURPOSE: To reduce the erroneous input of an operator by preliminarily storing origin coordinate data into a nonvolatile memory and automatically correcting the positional deviation between key positions of a touch panel and key display positions of a CRT.

CONSTITUTION: The position of the origin of key arrangement displayed on the screen of a CRT is defined as the origin of coordinate data of keys on a touch panel 15, and its coordinate data is stored into a non-volatile memory 3. When power is supplied to the touch panel 15, the origin of key arrangement displayed on the screen of the CRT is caused to correspond to the origin of keys on the touch panel 15, thereby automatically correcting the positional deviation.