A high-strength aluminum alloy consisting of an amorphous phase containing quasicrystals constituted of aluminum as the principal element, a first additive element consisting of at least one rare earth element and a second additive element consisting of at least one element other than aluminum and rare earth elements, and a crystalline phase consisting of the principal element and the first additive element and the second additive element contained in a supersaturated solid solution form, the amorphous phase containing quasicrystals being contained in a volume percentage of 60 to 90 %. The contents of the additive elements preferably fall within a hatched range in the figure, still preferably within a range covered with dot-dash lines in the figure.