A refractory brick having durability equal to alumina-magnesia castable materials, which is especially suitable for a ladle for steel making is provided. A refractory brick prepared by using an alumina raw material and a magnesia raw material containing 90% by mass or more of a fine powder of not more than 0.5 mm, press molding and then heat treating at 100° C. or higher and not higher than 1,150° C., the refractory brick containing Al2O3 and MgO in a total sum of 90% by mass or more, from 4 to 16% by mass of MgO, from 0.5 to 5% by mass of SiO2, and Na2O and K2O in a total sum of from 0.3 to 2% by mass, with the remainder being inevitable impurities and Al2O3.