disclosed is an epoxy resin type composition for stiffening a vehicle body . the epoxy resin type composition comprises an epoxy resin , a powdery methacrylate type polymer in an amount of 2 to 45 parts by weight relative to 100 parts by weight of the epoxy resin , a thermally active hardening agent for epoxy resin in an amount of 1 to 20 parts by weight relative to 100 parts by weight of the epoxy resin , a thermally decomposable foaming agent in an amount of 0 . 5 to 20 parts by weight relative to 100 parts by weight of the epoxy resin , and a mixture of an inorganic salt with a shape of a predetermined aspect ratio and a granular inorganic salt in an amount of 50 to 200 parts by weight relative to 100 parts by weight of the epoxy resin . a mixing ratio of the granular inorganic salt is 0 to 50 % by weight relative to the total amount of the mixture . also disclosed is a method for stiffening a vehicle body by use of such a composition .