To obtain a material having a low coefft. of thermal expansion and suitable for a heat generating support by mixing a mineral powder contg. a specified amt. of Li2O, a clay contg. a specified amt. of Al2O3 and a low viscosity refractory inorg. material in a specified ratio, molding the resultant compsn. to an arbitrary shape and carrying out firing.

A compsn. is prepd. by mixing 40-55 wt.% mineral powder contg. 3-6 wt.% Li2O, 25-35 wt.% clay contg. ≥30 wt.% Al2O3 and 15-25 wt.% low viscosity refractory inorg. material or further adding 3-7 wt.% compsn. contg. 10-50 wt.% one or more selected from Fe2O3, SiO and CrO. The mineral is preferably petalite, the clay is preferably kibushi clay and the inorg. material is preferably kaolin or agalmatolite. The prepd. compsn. is molded in an arbitrary shape and fired to obtain the objective material having a coefft. of thermal expansion of ≤3.0×10-6 at 1,000°C and less liable to crack even in about ≤5 mm thickness. The objective small-sized lightweight heat generating support is formed using the material and the objective electric furnace of 100 V-500 to 1,200 W for ceramic art is assembled using the support.