To display an intake pressure of an engine and a peak value of the intake pressure at the same time by providing a first display part which turns on or off a plurality of segments arranged in an array in accordance with the intake pressure, and a second display part displaying the peak value of the intake pressure numerically.

A display unit 4 comprises a fluorescent display device 5, a red light-emitting diode 6 and a yellow light-emitting diode 7 accommodated in a case 8. The fluorescent display device 5 comprises a first display part 10 having segments 9 arranged in an array to shape a schematic ellipse and a second display part 12 having segments 11 arranged in the shape of a numeral 8. When a driver depresses a mode selection switch 15 of a control unit 13 thereby to set a normal mode, the first and second display parts 10, 12 interlock with each other to display a boost pressure. The first display part 10 turns on the segment 9 of a numeral corresponding to the boost pressure, while the second display part 12 displays the boost pressure by a numeral. In a peak hold mode, the first display part 10 displays the boost pressure changing every moment, and the second display part 12 displays a peak value of the boost pressure by a numeral.