Abstract: To provide a dustproofing material having superior dustproofness and having such superior flexibility as to fit in a further minute clearance typically of 0.10 to 0.20 mm. Disclosed is a foam dustproofing material which is a dustproofing material including a foam having a thickness of 0.1 to 1.0 mm, in which the foam has a micro cell structure with an average cell diameter of 10 to 65 ?m, has such characteristic properties as to give a load against repulsion of from 0.010 to 0.100 MPa upon compression to a thickness of 0.1 mm, and has an apparent density of 0.01 to 0.050 g/cm3. The foam preferably has a closed cell structure or semi-open/semi-closed cell structure. The foam dustproofing material may further include a pressure-sensitive adhesive layer on one or both sides of the foam. The pressure-sensitive adhesive layer is preferably present above the foam through a film layer.