To easily provide recesses or projections for reducing separation of air currents on the exterior of a car body of an automobile.

This air current separation reducing sheet to be applied to the exterior of an automobile is provided with a plurality of recesses formed in the surface, and an adhesive layer formed on the back surface. By thus providing the adhesive layer on the back surface of the sheet provided with the plurality of the recesses, the sheet can be cut in a corresponding form to a necessary part in the exterior of the automobile, so that it is applied to simply provide the recesses for reducing separation of air currents in the surface of the exterior of the automobile.