Abstract: In a head-up display apparatus for a vehicle, there are employed, a fluorescent display tube having a filament, a grid, and an anode positioned in a predetermined positional relationship; a power supply circuit for supplying a filament current to the filament of the tube and an anode voltage to the anode thereof; a display controller coupled to a display switch, for controlling the display tube so as to display various information of a vehicle on the display tube in response to a vehicle information signal and a switch signal of the display switch, the display switch being operated so as to display/erase the various information on/from the tube; and, a synchronized switching unit for controlling the supply of the filament current to the filament from the power supply circuit in synchronism with the switching signal of the display switch supplied from the display controller.