An adhesive, comprising (A) a polymeric MDI, (B) modified polyvinyl acetate emulsion, (C) aqueous polyvinyl alcohol solution, and (D) a filler. Preferably, a mass ratio of A:B:C:D is 30:(60 160):(50 160):(10 140) provided that the aqueous polyvinyl alcohol solution (C) is in a concentration of 10% by mass.