In an MRI apparatus having an open structure, vibration caused by eddy current is reduced with keeping the magnetic field shielding capability of a high frequency shield disposed between a gradient magnetic field coil and a high frequency coil. The high frequency shield comprises two conductive sheets 501, 503 which are divided into plural parts at different positions, and a dielectric sheet 502 sandwiched therebetween. Accordingly, in the high frequency shield, the electric resistivity to high frequency magnetic field is lower than the electric resistivity to the switching frequency of gradient magnetic field, whereby the high frequency shield can act as a uniform conductor to the high frequency magnetic field, exercise the shielding capability of the high frequency magnetic field, reduce eddy current occurring due to passage of gradient magnetic field therethrough and suppress vibration.