A display input device includes a reception processing portion, a change processing portion, and a display processing portion. The reception processing portion, based on correspondence information indicating a correspondence between a plurality of characters and a plurality of operation keys used for inputting a password of a preset number of characters, receives an operation of any one of the operation keys as an input operation of a character corresponding to the operation key. The change processing portion changes the correspondence relationship when the operation of the operation key is performed a preset specific number of times that is less than the number of characters of the password, or at a preset specific interval. The display processing portion displays the correspondence information at a predetermined position, different from a position of the operation keys, on an input screen used for inputting the password.