PROBLEM TO BE SOLVED: To provide a method for manufacturing an AlSiCpowder capable of improving, as an antioxidant for an MgO-C brick, the oxidation resistance more effectively than its counterpart synthesized by an electric furnace heating method; a method for manufacturing an MgO-C brick to which the AlSiCpowder manufactured by the former manufacturing method has been added; and an MgO-C brick manufactured by using the same.SOLUTION: In the provided method for manufacturing an AlSiCpowder, an AlSiCpowder having an average particle diameter of 1 μm or less is manufactured by heating, with microwaves, a mixed powder of metallic Al, metallic Si, and C in an inert gas atmosphere. In the provided method for manufacturing an MgO-C brick, furthermore, the AlSiCpowder thus obtained is added to raw ingredients of an MgO-C brick during compounding at a ratio at least equivalent to respectively added quantities of a binder and a resin.
