Abstract We constructed an automatic crystal pulling system for YBa 2Cu 3O 7−x(Y123) and made a round cornered single crystal by keeping its growth temperature around its peritectic temperature. The size of the round shape crystal was 4 mm in diameter and 4 mm in length. A seed crystal was remelted at its corner first, and after the rounded cornered crystal was grown. Along the vertical axis, the crystal corner became wavy. The remelting process was explained by free energy difference between the flat interface to the square one. Growth shapes of the round corner were explained by temperature dependent growth rate anisotropy.