Abstract: A torque sensor comprising a magnetic amorphous film whose magnetostrictive characteristics vary with the amount of torque applied thereto and coils for detecting magnetostrictive variation disposed opposite the magnetic member. The torque sensor is constituted as an independent unit separate from the shaft whose torque is to be measured. The independent unit comprises a tubular or a shaft member having the magnetic amorphous film attached thereto and a housing with the coils at its inner wall. The housing covers the tubular or shaft member and is rotatable about the same axis as the member. The tubular member is easily mounted on the shaft through spline fittings in one embodiment and the short shaft member of the other embodiment is easily mounted between the two shaft ends via spline fittings and flange couplings.