In a unit for setting a function of a displayed menu, a choosing and displaying operation of selecting one of a plurality of groups of a menu and displaying all the functional particulars belonging to the chosen group chosen from the plurality of divided groups of the menu, on a same screen page of a display is performed, a choosing operation of selecting one of the plurality of functional particulars displayed on the display and a choosing and setting operation of selecting and setting one of a plurality of functional condition values displayed on the display corresponding to the selected functional particular are performed, and a displaying operation of displaying the plurality of the functional condition values which correspond to the selected functional particular.