In the MRI device of open structure, while maintaining the magnetic field cover ability of the high frequency seal which is arranged with the inclined magnetic field coil and the high frequency coil, there are times when it decreases the vibration which originates in the eddy current. The high frequency seal 2 conductor seats 501,503 which are divided into plural at the position where it differs mutually and, includes with the dielectric seat 502 which was put between that. Because of this, as for the high frequency seal, the electric electrical resistivity for the high frequency magnetic field, becomes lower than the electric electrical resistivity for the switching frequency of the inclined magnetic field. Because of this, it to be possible the fact that it operates vis-a-vis the high frequency magnetic field as the even conductor, as cover ability of the high frequency magnetic field can be shown, be able to decrease the eddy current which it occurs with passing the inclined magnetic field, the vibration can be controlled.オープン構造のMRI装置において、傾斜磁場コイルと高周波コイルとの間に配置される高周波シールドの磁場遮蔽能力を維持しながら、渦電流に起因する振動を低減することにある。高周波シールドは、互いに異なる位置で複数に分割された2枚の導体シート501,503と、その間に挟まれた誘電体シート502とを含む。これにより、高周波シールドは、高周波磁場に対する電気的抵抗率が、傾斜磁場のスイッチング周波数に対する電気的抵抗率よりも低くなる。これにより、高周波磁場に対しては一様な導体として作用することができ、高周波磁場の遮蔽能力を発揮できるとともに、傾斜磁場の通過により生じる渦電流を低減でき、振動を抑制できる。
