Commercial pellets are classified into 6 types according to the chemical composition of gangue: SiO//2-type, (SiO//2 plus Al//2O//3)-type, high total Fe-type, CaO-type, (CaO plus MgO)-type, and others. This paper evaluates high temperature-reducing properties of 44 kinds of pellets. In pelletizing low grade ores, addition of MgO-contained minerals contributed to improvement of high temperature properties. In acid pellets, the range of SiO//2/(SiO//2 plus Al//2O//3)ratio equals 0. 75 minus 0. 85 in raw ores should be avoided.