An object of the present invention is to provide a magnetic field application device that can arbitrarily set the conversion period of an external magnetic field, can be easily manufactured at low cost, and can be stably operated with low labor. The means for solving the problem includes a measurement part fixed at a predetermined position, an electrospin resonance electromagnet placed opposite to the position sandwiching the measurement part, and a current that supplies, adjusts and stops the current supplied to the electromagnet While the current is stopped with respect to the control mechanism and the electron spin resonance electromagnet, it exists opposite to the position sandwiching the measurement site, and while the current is supplied to the electron spin resonance electromagnet, the measurement site A magnetic field application apparatus comprising: a nuclear magnetic resonance magnet that does not exist at a position that sandwiches a magnetic resonance resonance magnet； and a nuclear magnetic resonance magnet moving mechanism that disposes and disposes the nuclear magnetic resonance magnet at a position that sandwiches a measurement site.発明の課題は、外部磁場の変換周期を任意に設定でき、簡単に低コストで製造することができ、低労力で安定した運転が可能な磁場印加装置を提供することである。課題の解決手段は、所定の位置に固定された測定部位と、測定部位を挟む位置に対向して設置された電子スピン共鳴用電磁石と、該電磁石に対して電流を供給し調節し停止する電流制御機構と、電子スピン共鳴用電磁石に対して電流が停止されている間は測定部位を挟む位置に対向して存在し、電子スピン共鳴用電磁石に対して電流が供給されている間は測定部位を挟む位置に存在しない核磁気共鳴用磁石と、核磁気共鳴用磁石を、測定部位を挟む位置に配置し撤収する核磁気共鳴用磁石移動機構とを、備える磁場印加装置である。
