To easily and certainly mount a protecting material on a ceiling material, a trim, or a car body, by using an adhesive sheet where an adhesive layer is formed on a base material composed of foam material.

In mounting a head protecting material 1 to a ceiling material 2 or the like, an adhesive tape 3 where an adhesive layer 3B is formed on a base material 3A composed of foam material is used. As the foam material constituting the base material of the adhesive sheet 3, variable foam material such as soft polyurethane foam, polypropylene, polyolefin resin foam such as polyethylene, or foam rubber is used. Its density is in a given range. The foam material with high density is hard, and therefore, cannot follow deformation and fully provide a fallout preventing effect of the head protecting material 1. The foam material with low density is low in strength, breaks during handling, easily fatigues, and therefore is not practical. Thus, the protecting material 1 can be easily, certainly, and strongly mounted even on a component that might receive large deformation or impact after mounting.