To provide an MRI apparatus employing an open type magnet structure suitable from an aspect of safety control by restricting a magnetic field intensity range exerting effect on peripheral machinery in a magnet arranged chamber and to use machinery high in operability employing a color CRT of high resolving power in the periphery of the magnet arranged chamber.

A superconductive coil 13 and a shield 14 are incorporated in a static magnetic field generating magnet 2. The magnetic flux at the center of a magnetic field has, for example, high magnetic field intensity of 0.5 millitesla and the shape and weight of the shield 14 is set so as to minimize a distribution range wherein a leak magnetic field is 0.5 millitesla. Further, the leak magnetic field to the outside of a shield room 15 is set to 0.1 millitesla or less by combining a silicon steel plate 27 with a part of the wall surface of the shield room 15. By this constitution, a color CRT display 12 displaying the operation data or examination result of the MRI apparatus can be arranged in close vicinity to the shield room 15.