A contactless detection apparatus has a first magnet ring, a second magnet ring, a first magnetic sensor, a second magnetic sensor and a controller. The two magnet rings are respectively mounted on two ends of a torsion shaft. When the torsion shaft rotates, the controller detects the magnetic fields of the two magnet rings through the two magnetic sensors. The controller calculates a twisting torque exerted on the torsion shaft and a rotational angle of the torsion shaft according to the detected magnetic fields at the same time. The detection apparatus of the invention has simple structure. The magnetic fields of both magnet rings do not interfere with each other, such that the detection result of the invention is accurate.