6. The input apparatus according to claim 1 , wherein when the inputted character string includes a kanji or a kana character after confirmation and the input to the key of the input unit is determined as the second input mode by the input mode determination unit, the input control unit searches, among the inputted character string displayed on the display unit, kana characters corresponding to the kana characters assigned to the key as the correction character candidates.
9. The input apparatus according to claim 6 , further comprising a storage unit for storing history of kana characters used to input the character strings and history of segments used to confirm the inputted character strings respectively, wherein the input control unit further searches, among the inputted character strings displayed on the display unit, a kanji having phonetic kana characters starting from a kana character assigned to the key as a correction character candidate from the storage unit, and based on the history of the kana characters used to input the character strings and the history of segments used to confirm the inputted character strings respectively, controls so that a correction character candidate onto which the cursor is moved based on the second input mode is returned to kana characters before confirmation on the segment basis and is displayed on the display unit in an editable manner.