To make a highly perfect aluminum crystal, high purity aluminum was melted in high vacuum of 2×10⁻⁷ Pa for 2 h using a cold-crucible induction furnace. The surface of as-melted ingot had a metallic luster and heavy oxidization was not observed on the surface. In the ingot, a large cylindrical-single crystal with a diameter of 60 mm and a length of 40 mm grew and dislocation density in the crystal was about 10⁷ m⁻². Purity of the melted aluminum was estimated to be near 99.9999% from the residual resistivity ratio. A large amount of highly perfect aluminum crystal with ultra-high purity was produced by only melting of melting once, under an ultra-high vacuum.