Character input device and method for a mobile terminal

A character input device and method for a mobile terminal, which enables users to quickly and conveniently input mixed characters from various character types such as Korean "Hangeul" characters, upper and lower case English characters, and different fonts and symbols. The mobile terminal includes a plurality of keys, each key being assigned characters of at least two character types, and is previously set in a character input mode of one of the character types, while characters of another of the character types can be selectively input. The character input device comprises at least one temporary mode conversion key mounted on the mobile terminal and a memory for storing character codes of each of the character types assigned to each of the plurality of keys. A controller selects one of the previously set character input mode and a temporary character mode, based on an input of the temporary mode conversion key, and reads out and recognizes character codes of each character types from the memory according to the plurality of keys input and the selected character input mode.