Disclosed herein is a bio-soluble inorganic fiber with high tensile strength, manufactured in a method comprising: heating and melting a raw material which includes, on a weight basis, 60 to 80 percent of SiO.sub.2, 5 to 20 percent of MgO, 5 to 30 percent of CaO, 0.5 to 5 of Al.sub.2O.sub.3, and 0.1 to 5 of BaO, at a temperature of 1800 to 2100 degrees Celsius; and exposing the melting material to an air flow for fiber forming.