A contactless torque sensor (100; 200) for a steering system, which is installed between an input shaft (10; 60) connected to a steering wheel and an output shaft (20; 70) connected to a vehicle wheel to detect a twist generated by rotational operation of the steering wheel, comprising: a magnetic force generating part (110; 210) coupled to the input shaft (10; 60) and having a plurality of N pole magnets (114; 211a) and S pole magnets (115; 211b) alternatively on an outer circumferential surface thereof; a magnetic shield part (120; 220) having a shape of a hollow cylinder, coupled to the output shaft (20; 70) and having a plurality of holes (121, 122) to be located within areas of the N pole magnets (114; 211a) and the S pole magnets (115; 211b); a magnetic detection part (130; 230) provided at a distance from an outer surface of the magnetic shield part (120; 220) and detecting a magnetic force passing through a plurality of the holes (121, 122); and a magnetic detection sensor part (140; 240) located at an outer surface of the magnetic detection part (130; 230) to detect a change of a relative twist between the magnetic force generating part (110; 210) and the magnetic shield part (120; 220); characterized in that: the magnetic shield part (120; 220) comprises a first magnetic shield part that has first through holes formed at a predetermined interval therebetween on an upper outer surface and a second magnetic shield part that has second through holes formed at a predetermined intervals therebetween on a lower outer surface to be alternatively disposed with the first through holes; the magnetic detection part (130; 230) comprises a first magnetic detection member that detects a magnetic force passing through the first through holes, and a second magnetic detection member that is located at a distance from a lower side of the first magnetic detection member and detects the magnetic force passing through the second through holes. a magnetic force generating part (110; 210) coupled to the input shaft (10; 60) and having a plurality of N pole magnets (114; 211a) and S pole magnets (115; 211b) alternatively on an outer circumferential surface thereof; a magnetic shield part (120; 220) having a shape of a hollow cylinder, coupled to the output shaft (20; 70) and having a plurality of holes (121, 122) to be located within areas of the N pole magnets (114; 211a) and the S pole magnets (115; 211b); a magnetic detection part (130; 230) provided at a distance from an outer surface of the magnetic shield part (120; 220) and detecting a magnetic force passing through a plurality of the holes (121, 122); and a magnetic detection sensor part (140; 240) located at an outer surface of the magnetic detection part (130; 230) to detect a change of a relative twist between the magnetic force generating part (110; 210) and the magnetic shield part (120; 220); the magnetic shield part (120; 220) comprises a first magnetic shield part that has first through holes formed at a predetermined interval therebetween on an upper outer surface and a second magnetic shield part that has second through holes formed at a predetermined intervals therebetween on a lower outer surface to be alternatively disposed with the first through holes; the magnetic detection part (130; 230) comprises a first magnetic detection member that detects a magnetic force passing through the first through holes, and a second magnetic detection member that is located at a distance from a lower side of the first magnetic detection member and detects the magnetic force passing through the second through holes.