The forced air cooling portion 405A according to the present modification is achieved by dual use of an air conditioner 452A equipped in the vehicle V. The air conditioner 452A sends cooling air into the room of the vehicle V to cool the room, and includes a duct 452Aa and a nozzle 452Ab. The duct 452Aa is a laying pipe through which cooling air for cooling the room flows. The nozzle 452Ab is an outlet for blowing the cooling air flowing in the duct 452Aa, outward, and is provided such that the cooling air can be blown to each heat sink portion 245. The forced air cooling portion 405A blows part of the cooling air for cooling the room flowing in the duct 452Aa, to each heat sink portion 245 through the nozzle 452Ab, so that each heat sink portion 245 is forcibly cooled.

Even for the vehicular display device 401A as above, the air conditioner 452A serving as the forced air cooling portion 405A forcibly cools the heat sink portions 245, so that heat, such as condensing heat, conducted from either inner wall part 41A to the corresponding lower wall part 42A can be more efficiently dissipated outward. As a result, similarly to the vehicular display device 401, the vehicular display device 401A enables more reliable inhibition of a rise in the temperature of the casing 4, so that thermal degradation can be more reliably inhibited.

Furthermore, instead of the forced air cooling portions 405 and 405A as above, for example, provided may be a forced air cooling portion that forcibly cools each heat sink portion 245 with the wind of the traveling vehicle V as cooling air.