1. A text input support system for supporting input of text containing plural words separated from each other with spaces, the system comprising: a keyboard for entering a character string; a display device for displaying the entered character string and text; a storage device for storing a program and data; a processor for processing the character string entered by the keyboard in accordance with the program; and a dictionary registering all words that can be used for the text input and being stored in the storage device as the data; wherein the processor compares the entered character string with words registered in the dictionary one by one character from a leading character, memorizes a word that is identical to the entered character string, makes the word that was identical to the entered character string last time a fixed character string when it is decided there is no possibility that the entered character string will be identical to a word registered in the dictionary, and adds a space after the fixed character string so as to separate the character string from a subsequent input character string.