A user interface device which displays an operation key in a display unit using a predetermined design. The device includes: a history storing unit that stores a history record in which a content of a setting operation carried out by a user for each of past jobs that have been executed is recorded; a history retrieving unit that retrieves the history record in which the content of the setting that is the same as a current content of the setting is recorded; a calculating unit that calculates a total number of operations for each operation key based on the content of the setting recorded in the history record in which the same content of setting is recorded; and an operation key display type determining unit that estimates relative degrees of likelihood to be used by the user of the operation keys based on the total number of operations for each operation key, and determines, based on the estimation, a design to be used to display the operation key out of a group of designs including at least a first design for normal display and a second design for highlighted display.