Rotor of high speed induction motor and manufacturing method thereof

A rotor of an ultra high speed induction motor includes a stacked body having a plurality of loop type steel sheets stacked to form a cylinder, with a plurality of slots circumferentially formed in a lengthwise direction of the stacked body. Loop type upper, lower end rings are disposed on the upper and lower portions of the stacked body and having a plurality of upper and lower through-holes, respectively, to correspond to the slots. Conductive bars are coated with fusible bonding flux and are inserted into the upper through-holes, the slots, and the lower through-holes such that the conductive bars are integrally bonded into the upper through-holes, the slots, and the lower through-holes, following the fusion and solidification of the fusible bonding flux.