5. A location search method comprising: performing a character input process, wherein when one of a plurality of buttons in a character input portion is repeatedly pressed or pressed continuously for a given time or longer, a plurality of characters assigned in advance to the one button is displayed in an input character display portion in a predetermined cyclic sequence; when one of the plurality of buttons is pressed, and then, another of the plurality of buttons is pressed, the character displayed in the input character display portion immediately prior to pressing of the other button is set as an input set character whose input has been set; and when the character is input through the character input portion following the input set character, a character string is input; acquiring a search object character string that partially matches the input character string, as an input candidate character string, from a character string storage portion that stores a plurality of search object character strings; and assigning the input candidate character string to a character string button through which the input candidate character string is input, and displaying the input candidate character string assigned to the character string button; and creating a plurality of compound character strings by combining the input set character string whose input has been set with the plurality of characters assigned in advance to the button that is pressed next, and acquiring the search object character strings that partially match the respective compound character strings, as the input candidate character strings.
5. A location search method comprising: performing a character input process, wherein when one of a plurality of buttons in a character input portion is repeatedly pressed or pressed continuously for a given time or longer, a plurality of characters assigned in advance to the one button is displayed in an input character display portion in a predetermined cyclic sequence; when one of the plurality of buttons is pressed, and then, another of the plurality of buttons is pressed, the character displayed in the input character display portion immediately prior to pressing of the other button is set as an input set character whose input has been set; and when the character is input through the character input portion following the input set character, a character string is input; acquiring a search object character string that partially matches the input character string, as an input candidate character string, from a character string storage portion that stores a plurality of search object character strings; and assigning the input candidate character string to a character string button through which the input candidate character string is input, and displaying the input candidate character string assigned to the character string button; and creating a plurality of compound character strings by combining the input set character string whose input has been set with the plurality of characters assigned in advance to the button that is pressed next, and acquiring the search object character strings that partially match the respective compound character strings, as the input candidate character strings. 8. The location search method according to claim 5 , wherein the search object character string whose first portion matches the input set character string is acquired as the input candidate character string.