A view adjustment portion includes a vertex at a position offset from a driver between a position opposed to the driver and a center position of the vehicle and includes right and left edges uniformly sloped down from the vertex toward each side in the vehicle width direction. On the interior surface of the view adjustment portion, textures densest and smallest in the vicinity of the vertex are provided. This can prevent the driver's visual focus to be directed to the vicinity of the vertex T and guide the driver's visual focus in the travel direction of the vehicle. Accordingly, it is possible to prevent the driver from feeling disturbance by a portion of the view adjustment portion around the vertex.