PURPOSE: To reduce an amount of whiskery material by heating mixed granules of SiO2 and C in a rotary furnace in a nonoxidizing atmosphere not containing N2 at a specific temperature.

CONSTITUTION: 100 pts.wt. SiO2 powder having ≤50μm particle diameter and 60-180 pts.wt. carbon powder having ≤5μm particle diameter are fed to a blending granulator, mixed with water having dissolved a small amount of polyethylene glycol, stirred at high speed, made into granules having 50μm to 5mm grain diameter, heated and dried to give mixed granules. Then the mixed granules are fed from a raw material hopper 1 of a continuous reducing carbonizing device through a blended granule feeder 2 to a shell 4 of a rotary furnace 3. The mixed granule is heated to 1,200-1,700°C by a heater 5, reduced and carbonized in a nonoxidizing atmosphere not containing N2 while rocking, and SiC is taken out from a carbide recovery container 6. Carbon in the prepared SiC powder is heated and oxidized and removed to give B-SiC having a small amount of whiskery material.