To automatically correct judgment criterion for judging that a one- character input is ended so as to be adapted for a user's skillful degree.

When coordinate data inputted from a coordinate input device 101 indicates the inside of a character input frame on a character input screen, a coordinate input part 102 judges a character input to the input frame. Then an input control part 104 judges the end of the one-character input by whether the input is the one to the input frame being different from the input frame where an input is performed immediately before the judgment or not or whether a no input time till this time input, which is counted by a timer 105, exceeds the setting time of a detection-end time setting part 106 or not. When coordinate data inputted from the device 101 indicates the inside of the area of a 'regression' button, the control part 104 erases the display of the last character in an editing area on the character input screen and resets the setting time of the part 106 to be a value with an increase for the portion of a prescribed time.