To cope with a problem wherein a password may be browsed by other person, and a problem wherein a memorandum of the password may be found or browsed by the other person, in storage thereof.

The password is formed based on a table by rotating a display part, according to a rule prepared by ownself, from a tentative password, an alphabet, a numeral, a symbol and the like are usable therein, and the number of figures and the number of windows of the password are freely formed therein. The person himself or herself is not required to know the password, and the password is input not to be known by the other person.