The purpose of the present invention is to quantitatively ensure the positional accuracy of the arrangement of shim members in passive shimming work on a magnet device of a magnetic resonance imaging device. This magnet device is provided with: one set of magnetic-field generation sources which are disposed facing each other in a vertical direction, and which generate a magnetic field in an imaging area and magnetic-field adjustment mechanisms (11L) or the like which are disposed facing each other in the vertical direction with the imaging area therebetween, and which adjust the uniformity of the magnetic field. The magnetic-field adjustment mechanisms (11L) or the like are each provided with: shim members (20) comprising magnetic bodies or permanent magnets and a shim-member fixation plate (19) which has a substantially circular or substantially polygonal outer peripheral shape, which has the surface thereof divided into a plurality of boxes (14), and in which the shim members (20) are fixed. Each of the boxes (14) quantitatively indicates the adjustment accuracy of each of the positions of the shim members (20) placed therein.La présente invention vise à garantir de manière quantitative la précision de positionnement de lagencement déléments de cale, lors dune homogénéisation de champ magnétique passive, sur un dispositif daimant dun dispositif dimagerie par résonance magnétique. Ce dispositif daimant comprend : un ensemble de sources de génération de champ magnétique qui sont disposées lune en face de lautre dans une direction verticale, et qui génèrent un champ magnétique dans une zone dimagerie et des mécanismes de réglage de champ magnétique (11L), ou analogue, qui sont disposés lun en face de lautre dans la direction verticale, avec la zone dimagerie entre eux, et qui règlent luniformité du champ magnétique. Les mécanismes de réglage de champ magnétique (11L), ou analogue, comprennent chacun : des éléments de cale (20) comprenant des corps magnétiques ou des
