A magnetic shield to be attached to a sensor device to surround a magnetic flux collecting ring from an outer side in a radial direction of a rotary shaft including a first shaft and a second shaft coupled to each other via a torsion bar, the sensor device including a permanent magnet fixed to the first shaft and magnetized in a circumferential direction of the first shaft, a magnetic yoke fixed to the second shaft and arranged in a magnetic field of the permanent magnet to surround the permanent magnet from the outer side in the radial direction, the magnetic flux collecting ring including a body (41a, 42a) arranged to surround the magnetic yoke from the outer side in the radial direction and a magnetic flux collecting portion (41b, 42b, 41c, 42c) extending outward in the radial direction from the body, and a magnetic sensor arranged in association with the magnetic flux collecting portion and configured to detect a magnetic flux of a magnetic circuit including the permanent magnet, the magnetic yoke, and the magnetic flux collecting ring, the magnetic shield comprising a divided portion divided in the circumferential direction into two parts (71, 72) before attachment to the sensor device, wherein the two parts, being a first part and a second part, are provided separately from each other in the circumferential direction, and have a symmetrical structure, the divided portion is integrated by bringing the two parts (71, 72) close to or in contact with each other during the attachment to the sensor device, the divided portion in an integrated state includes a first shield portion that surrounds the body of the magnetic flux collecting ring from the outer side in the radial direction, and a second shield portion that surrounds the magnetic flux collecting portion of the magnetic flux collecting ring together with the magnetic sensor to extend outward in the radial direction from the first shield portion, the first part has a first body segment of two body segments (71a, 72a) into which the first shield portion is divided at a first boundary portion in the circumferential direction, and a first sensor segment of two sensor segments (71c, 72c) into which the second shield portion is divided at a second boundary portion in the circumferential direction, and the second part has a second body segment of the two body segments (71a, 72a) into which the first shield portion is divided at the first boundary portion in the circumferential direction, and a second sensor segment of the two sensor segments (71c, 72c) into which the second shield portion is divided at the second boundary portion in the circumferential direction. the two parts, being a first part and a second part, are provided separately from each other in the circumferential direction, and have a symmetrical structure, the divided portion is integrated by bringing the two parts (71, 72) close to or in contact with each other during the attachment to the sensor device, the divided portion in an integrated state includes a first shield portion that surrounds the body of the magnetic flux collecting ring from the outer side in the radial direction, and a second shield portion that surrounds the magnetic flux collecting portion of the magnetic flux collecting ring together with the magnetic sensor to extend outward in the radial direction from the first shield portion, the first part has a first body segment of two body segments (71a, 72a) into which the first shield portion is divided at a first boundary portion in the circumferential direction, and a first sensor segment of two sensor segments (71c, 72c) into which the second shield portion is divided at a second boundary portion in the circumferential direction, and a first body segment of two body segments (71a, 72a) into which the first shield portion is divided at a first boundary portion in the circumferential direction, and a first sensor segment of two sensor segments (71c, 72c) into which the second shield portion is divided at a second boundary portion in the circumferential direction, and the second part has a second body segment of the two body segments (71a, 72a) into which the first shield portion is divided at the first boundary portion in the circumferential direction, and a second sensor segment of the two sensor segments (71c, 72c) into which the second shield portion is divided at the second boundary portion in the circumferential direction. a second body segment of the two body segments (71a, 72a) into which the first shield portion is divided at the first boundary portion in the circumferential direction, and a second sensor segment of the two sensor segments (71c, 72c) into which the second shield portion is divided at the second boundary portion in the circumferential direction.