The nuclear magnetic resonance device which has the magnetic field formation vessel, and this magnetic field formation vessel which are formed in the magnetic circuit of the open magnetic circuit which can form the uniform magnetic field with briefer structure is offered. As direction of magnetization is directed to reference direction, the 1st permanent magnet which is consecutively arranged across specified interval and touching the 2nd permanent magnet and with of the 1st permanent magnet and the 2nd permanent magnet, mutually in this reference direction according to reference direction, or it has with the 3rd permanent magnet and the 4th permanent magnet which consecutively it arranges across specified interval, direction of magnetization of the 3rd permanent magnet the 1st component which is parallel with reference direction and, 1st direction crossing, has with the 2nd component which it directs to territory sideIt makes direction, direction of magnetization of the 4th permanent magnet, the 1st component and, direction of the 2nd component and being backward, as the 2nd component makes the magnetic field formation vessel of the open magnetic circuit type which is made the direction which possesses the reversal 2nd component which is made the same size.より簡潔な構造で均一な磁界を生成することができる開磁路の磁気回路で構成した磁界生成器、及びこの磁界生成器を備えた核磁気共鳴装置を提供する。基準方向に磁化の方向を向けるとともに、この基準方向に所定の間隔を隔てて順次配置した第1の永久磁石と第2の永久磁石と、第1の永久磁石と第2の永久磁石との間に、基準方向に沿って互いに接してまたは所定の間隔を隔てて順次配置した第3の永久磁石と第4の永久磁石とを備え、第3の永久磁石の磁化の方向は、基準方向と平行な第1成分と、第1の方向と直交して領域側に向けた第2成分とを有する方向とし、第4の永久磁石の磁化の方向は、第1成分と、第2成分の向きと逆向きで第2成分と同じ大きさとした反転第2成分とを有する方向とした開磁路型の磁界生成器とする。
