To prevent the lowering of adhesion by successively laminating a cushioning material layer, a pressure-sensitive adhesive layer and a release sheet on the rear of a flooring wooden board material and using butyl rubber pressure-sensitive adhesives as the side brought into contact with the release sheet of the pressure-sensitive adhesive layer.

A cushioning material layer 2, which consists of a synthetic resin foam composed of a polyolefin resin, a polyurethane resin, etc., and a nonwoven fabric, etc., and in which a surface is formed in an irregular surface 21, is laminated on the rear of a flooring wooden board material made up of plywood, a fiberboard, etc. A double-coated adhesive tape 4, in which a butyl rubber pressure-sensitive adhesive layer is formed on both surfaces of the nonwoven fabric, a synthetic resin film, etc., is laminated on the peeling treating surface of a release sheet 5. The double-coated adhesive tape 4 is laminated on the irregular surface 21 of the cushioning material layer 2 together with the release sheet 5, and a soundproof flooring material 3 with the pressure-sensitive adhesive layer is formed. Accordingly, even when the soundproof flooring material is cladded onto a mortar or concrete surface, the lowering of adhesion can be prevented because water resistance and resistance to moist heat are improved.