An apparatus for inputting characters and method thereof are disclosed, by which a character can be inputted at high speed in a manner of implementing a new character set and by which a character can be inputted at high speed using a new character set and a rotatable moving key. The present invention includes an input unit comprising a plurality of roller type keys, each generating a rotation-associated keying signal or a pressing-associated keying signal and a plurality of selection keys, each generating the pressing-associated keying signal and a controller performing a character set search by a character set unit according to the rotation-associated keying signal, the controller performing a character input according to the pressing-associated keying signal.