An induction torque motor, TM, comprising: a stator ; and a rotor , the rotor comprising: a shaft member ; and a cylindrical member concentrically connected to the shaft member , the cylindrical member being formed of a soft magnetic material having a specific electric resistivity lower than or equal to 0.4 μΩ·m and a relative permeability higher than or equal to 1000 and lower than or equal to 50000, wherein: let T be the torque of the induction torque motor, TM, in N·m, let P be the eddy current loss of the rotor in W/kg, let s be the slip of the induction torque motor, TM, let f 0 be the drive frequency of the induction torque motor, TM, in Hz, let ρ be the specific electric resistivity of the soft magnetic material in μΩ·m, let μ be the relative permeability of the soft magnetic material, and let δ(sf 0 ) be the skin depth of the cylindrical member at a drive frequency of f 0 in m, and when a symbol oc in a mathematical statement "A oc B" indicates that A is proportional to B, the torque T per "loss P/slip sf 0 " is defined as: T / P / sf 0 ∝ 1 / 1 + a / μ ⋅ δ sf 0 / ρ the parameter a in the previous equation is inversely proportional to a distance G between the outer peripheral surface of the cylindrical member of the rotor and the inner peripheral surface of the stator , the induction torque motor, TM, being characterized in that the distance G is in a range 0.1 mm ≤ G ≤ 0.15 mm defining the parameter a as being in the range 1000 ≤ a ≤ 2500. a stator ; and a rotor , the rotor comprising: a shaft member ; and a cylindrical member concentrically connected to the shaft member , the cylindrical member being formed of a soft magnetic material having a specific electric resistivity lower than or equal to 0.4 μΩ·m and a relative permeability higher than or equal to 1000 and lower than or equal to 50000, a shaft member ; and a cylindrical member concentrically connected to the shaft member , the cylindrical member being formed of a soft magnetic material having a specific electric resistivity lower than or equal to 0.4 μΩ·m and a relative permeability higher than or equal to 1000 and lower than or equal to 50000, wherein: let T be the torque of the induction torque motor, TM, in N·m, let P be the eddy current loss of the rotor in W/kg, let s be the slip of the induction torque motor, TM, let f 0 be the drive frequency of the induction torque motor, TM, in Hz, let ρ be the specific electric resistivity of the soft magnetic material in μΩ·m, let μ be the relative permeability of the soft magnetic material, and let δ(sf 0 ) be the skin depth of the cylindrical member at a drive frequency of f 0 in m, and when a symbol oc in a mathematical statement "A oc B" indicates that A is proportional to B, the torque T per "loss P/slip sf 0 " is defined as: T / P / sf 0 ∝ 1 / 1 + a / μ ⋅ δ sf 0 / ρ the parameter a in the previous equation is inversely proportional to a distance G between the outer peripheral surface of the cylindrical member of the rotor and the inner peripheral surface of the stator , the induction torque motor, TM, being characterized in that the distance G is in a range 0.1 mm ≤ G ≤ 0.15 mm defining the parameter a as being in the range 1000 ≤ a ≤ 2500. <EOS>