1. A command inputting method used when inputting characters using software for Kana (Japanese character)-to-Chinese character conversion comprising the steps of: receiving a string comprising a plurality of characters through a keyboard; determining whether the character string is a command or not by looking up the string in command information comprising a command correlated to a character string; executing a corresponding command when it is determined in the determining step that the string is a command; and replacing the string with at least one corresponding Chinese character when it is not determined that the character string is a command.