PURPOSE: To simplify the structure, simplify the installation and moderate the resistance of air striking on an advancing directional front wall of a cargo chamber during the traveling.

CONSTITUTION: A baffle plate device for a truck has an integrally molded baffle plate 12 and a fixing mechanism to fix this baffle plate 12 above a truck driver's seat, and the baffle plate 12 has a bending part 13 which is supported in a cantilever shape with this baffle plate 12 by an almost U-shaped or elliptic slit 13a and whose tip edge approaches forward in the advancing direction of the ceiling 10b of the truck driver's seat 10, and has a sun visor part 14 covering an upper part of front glass 10a of the truck driver's seat 10, an opening part 15 to let air striking on the front glass 10a escape above this baffle plate 12 and an air introducing part 12 to deflect the air striking on the front glass 10a and air from the truck front upward to a cargo chamber 11. This baffle plate 12 is molded by transparent resin, and a diagram and a character can be left in an optional position of a transparent part by masking painting.