A torque sensor for a steering system according to an aspect of the present disclosure includes a first magnetic body having an open region and an unopened region arranged in an alternating manner along a circumference of a circular connecting member, the open region and the unopened region facing a magnet having N and S poles arranged in an alternating manner in a circular shape, the magnet installed at one end of a torsion bar, the first magnetic body connected to the other end of the torsion bar; a second magnetic body placed facing the magnet along an outer periphery of the magnet with the first magnetic body interposed between the second magnetic body and the magnet; a third magnetic body placed facing the first magnetic body while failing to face the magnet; and a magnetic sensing member placed between the second magnetic body and the third magnetic body.