The present invention is directed to provide an induction motor having an ideal efficiency at the normal operation time, while obtaining a high locked-rotor torque without having to use a special drive circuit. According to the induction motor related to the present invention, the induction motor has a rotor 11 having a double squirrel-cage secondary conductor, wherein the rotors 11 includes a rotor core 11a formed by laminating a plurality of electromagnetic steel plates, outer layer slots 40a filled with conductive material, installed along an outer peripheral edge of the rotor core 11a, inner layer slots 40b filled with conductive material, disposed inside of the outer layer slot 40a in the radial direction, and inner peripheral thin bridges 82 made of electromagnetic steel plate, installed in between the outer layer slots 40a and the inner layer slots 40b.