1. An alphabetic character input device comprising: a key input section comprising a first key group having input keys mapped with first half patterns of certain alphabetic characters which are each divided into a pair of half patterns and, a second key group having input keys mapped with second half patterns of said certain alphabetic characters, and undivided alphabetic characters are mapped on input keys of either the first or second key groups; a memory for storing a table that maps the input keys of the first and second key groups with the first and second half patterns of said certain alphabetic characters and said undivided alphabetic characters; and a control section for recognizing an input of an alphabetic character when a key is pressed that was mapped with one of the undivided alphabetic characters, and for combining first and second half patterns when keys mapped with the first and second half patterns are consecutively pressed, thereby recognizing the combined patterns as a single alphabetic character.