PURPOSE: To attain the input of a long numeral string with the small key touch frequency by using a means which puts a specific character string between a comma and a prescribed character inputted after the comma.

CONSTITUTION: When a comma is inputted in a half size of a character via a character input part 11 after '1' is transmitted and displayed at a display part 16, the comma is sent to the part 16 and displayed there. Then a return key is inputted via the part 11 and an input character discriminating part 12 detects that the comma is stored in an input character storage part 13 and sends the comma to an input character processing part 14. The part 14 produces a character of '' based on a character format stored in the part 13 and sends it to the part 16 together with the input character when a specific character is inputted from a character table 15. As a result, a long numeral string can be inputted with the small key touch frequency.