PROBLEM TO BE SOLVED: To provide a magnetic detection sensor that can easily recover the sensitivity of magnetism detection without having to adjust the optical path even if a magnetic reaction unit is replaced.SOLUTION: A magnetic sensor 4 is equipped with a magnetic reaction unit 34 having a gas cell 53 filled with gas that rotates the polarization plane of a laser beam 43 passing correspondingly to the intensity of a magnetic vector 58, a light guiding unit 38 that guides the laser beam 43 to the magnetic reaction unit 34 and a light detecting unit 41 that detects the rotation angle of the polarization plane of the laser beam 43 having passed the magnetic reaction unit 34. The light guiding unit 38 and the light detecting unit 41 are fixed in their relative positions, and the magnetic reaction unit 34 is fitted detachably to the light guiding unit 38 and the light detecting unit 41.SELECTED DRAWING: Figure 6COPYRIGHT: (C)2017,JPO&INPIT【課題】磁気反応部を交換しても光路の調整をすることなく、簡便に磁気を検出する感度を回復できる磁気検出センサーを提供する。【解決手段】磁気センサー4は磁気ベクトル58の強度に対応して通過するレーザー光43の偏光面を回転させる気体が充填されたガスセル53を有する磁気反応部34と、磁気反応部34にレーザー光43を導光する導光部38と、磁気反応部34を通過したレーザー光43の偏光面の回転角を検出する光検出部41と、を備え、導光部38と光検出部41とは相対位置が固定され、磁気反応部34が導光部38及び光検出部41に対して着脱可能に設置される。【選択図】図6
