A tape-shaped insulating material comprises an insulating substrate and a pressure-sensitive adhesive layer provided on one side or both sides of the substrate, wherein the pressure-sensitive adhesive layer is made of an aqueous dispersion type acrylic pressure-sensitive adhesive containing a polymer emulsion that is a product of emulsion polymerization of a monomer mainly composed of C.sub.4 to C.sub.12 alkyl(meth)acrylate ester in the presence of an emulsifying agent. The tape-shaped insulating material has an electrolytic corrosion coefficient according to JIS C-2338 of 0.98 or more, and the pressure-sensitive adhesive layer has good insulating characteristics.