The amount of time that a subject is under the static magnetic field of a rotating-type MRI device is dependent on the rotational-direction width of a magnet. Conventional rotating-type MRI devices require that the width of the magnet be altered in order to alter the amount of time that the subject is under the static magnetic field. Provided is a measurement device that is provided with: a first magnet that is provided in a first range that is on a circle that is centered on a rotating shaft a second magnet that is provided in a second range that is on a circle that is centered on the rotating shaft, the second range being different from the first range a drive unit that rotates the first magnet and the second magnet around the rotating shaft a measurement unit that is for measuring a measurement target that is in an installation position to which is applied a first magnetic field that is generated by the first magnet as a result of the rotation of the rotating shaft and a second magnetic field that is generated by the second magnet as a result of the rotation of the rotating shaft and a control unit that, while the measurement target is being measured, changes the rotating speed of the rotating shaft in accordance with the position of the first magnet and the second magnet with respect to the installation position.La quantité de temps pendant laquelle un sujet est sous le champ magnétique statique dun dispositif dIRM de type rotatif dépend de la largeur de la direction de rotation dun aimant. Les dispositifs dIRM du type rotatif classique requièrent que la largeur de laimant soit modifiée de façon à modifier la quantité de temps pendant laquelle le sujet se trouve sous le champ magnétique statique. Linvention concerne un dispositif de mesure qui est pourvu : dun premier aimant qui est prévu dans une première plage qui est sur un cercle qui est centré sur un arbre rotatif dun second aimant qui est prévu dans une seconde plage qui est sur un cercle qui est centré s
