VEHICLE DISPLAY DEVICE

A vehicle display device (1) includes a display device (5), a reflecting mirror (3), an optical sensor (41) configured to detect external light (SL), and a controller (7) configured to enable execution of a temperature lowering operation. The display device (5) includes a light transmissive liquid crystal display unit (21) disposed on an optical path of light emitted from a light source (32) and a first optical member (33) disposed between the liquid crystal display unit (21) and the light source (32) and configured to change an optical path of light that enters the first optical member (33) from the light source (32) and passes therethrough toward the liquid crystal display unit (21). The optical sensor (41) is disposed on an optical path of the external light (SL) incident on the display device (5) at a side opposite to the liquid crystal display unit (21) across the first optical member (33). The first optical member (33) includes a passage (33a) on an optical path through which the external light (SL) passes.