A gallium alloy for dental restorations which is hardenable at mouth temperature or around 37.degree. C. or more after triturating multicomponent liquid gallium alloy with alloy powder, is disclosed. The mixture has a heterogeneous structure after hardening, and contains as the overall composition, 9-47% gallium, 1-35% indium, 0.2-38% tin and 1-68% silver as indispensable components and one or more elements selected from 0.4-35% palladium, 0.5-25% copper and 0.4-12% zinc as arbitrary components. The multicomponent liquid gallium alloy contains 45-85% gallium, 5-40% indium and 1-30% tin as fundamental components and small amounts one or more elements selected from silver, palladium, gold, platinium, copper, zinc and germanium as arbitrary components. The alloy powder contains 1-85% silver and two or more elements selected from 1-40% tin, 1-40% palladium, 1-30% copper, 1-15% zinc and 1-25% indium. Also, the alloy powder is used with one or more single metal powder selected from palladium, platinium, gold, silver, copper and tin and/or powdered alloy containing one or more of said metals in which said single metal powder and said powdered alloy consist of a spherical or near spherical-irregular particle shape having particle size different from those of said alloy powder or a flat or flaky particle shape.