The invention relates to a non-contact phase-difference type torque sensor which comprises an input sleeve, an output sleeve, a Hall sensor, a first involute gear and a second involute gear, wherein the input sleeve is connected with the output sleeve through a torsion bar, a hub bore of the first involute gear is in interference fit with the output sleeve, a hub bore of the second involute gear is in interference fit with the input sleeve, third sections of shaft segments of the input sleeve and the output sleeve are respectively matched with an inner ring of a corresponding bearing, an outer ring of the bearing is respectively matched with two groups of sensor shells which are arranged at two sides of the torsion bar, a magnetic circuit support is respectively fixed on the inner surface of each sensor shell, a magnetic circuit assembly and a circuit board are fixed on each magnetic circuit support, the Hall sensor is welded on the circuit board, and a detection surface of the Hall sensor is arranged in an air gap where the end surface of magnetic-conducting soft iron a just faces to a top addendum circle of the involute gear. The invention has the advantages of simple structure, accurate test, good stability, comparatively lower cost, and the like.