Abstract: A method of setting a password and a method of authenticating a password in a portable device having a small number of operation buttons. The method of setting a password includes: determining whether there is an input through the operating of an operation button within a predetermined time; displaying a symbol of the operated operation button, when there is an input through the operating of an operation button within the predetermined time; and setting displayed symbols as a password required for using the portable device, when there is an input through the operating of an operation button for representing an end of an input of symbols. Accordingly, the password can be set by operating operation buttons in the portable device having no text or number buttons. Authentication of a password can be performed by using the set password.