To exert an excellent air curtain effect and to improve degree of freedom in design of a spoiler.

A rear spoiler 1 has a main body 11 of which an upper face 1a is formed to be a concave plane connected to a rear edge 31 of a vehicle roof. The bottom of the upper face 1a of the main body 11 comprises an opening 14 which pierces the main body 11 downward and the opening 14 is positioned lower than the rear edge 31 of the vehicle roof. Air running along the vehicle roof flows into the opening 14. Then the air is dammed by a rear internal wall 141 thereof and at the same time changes its flowing direction to downward. The air flow is directed to a glass surface of a rear window glass 21 to form air curtain.