FIELD: production of mineral fibers. SUBSTANCE: mineral material melt with viscosity below 5000 poise at temperature of liquids above 1200 C is centrifuged to form threads. The latter are additionally thinned when affected by gas flow, its configuration being such that most thread-forming cones coming out of centrifuge holes reach zone cooled to temperature corresponding to viscosity higher than 100 poise. Lengths of thread- forming cones are adjusted by varying diameter of holes in wall of centrifuge and/or varying centrifuge rotation speed. Device for forming fibers via internal centrifugation contains centrifuge with multiple holes in its outside wall, external concentric ring torch arranged concentrically with regard to centrifuge, and external ring air blower arranged concentrically with regard to external concentric ring torch. The latter is positioned at distance 15-30 mm above upper side of outside wall of centrifuge. Diameter of inside wall of outlet channel of the torch is less than diameter of upper part of centrifuge outside wall. Vertical walls of outlet channel of the torch are joined with inclined walls which determine expanding outlet stream of hot gases. EFFECT: improved design. 11 cl, 7 dwg, 1 tbl
