PURPOSE: To reduce electromagnetic mutual interference with other units and minimize dielectric loss by limiting high frequency electric field induced by high frequency coil to be used for apparatus for examination by magnetic resonance to a minimum space and consequently secure examination data with high S/N ratio and reduce heat generation by dielectric heating of a subject.

CONSTITUTION: Current paths vertical 1, 2, consisting of plural ones and placed parallel to the axis of a cylinder, are arranged on the surface of a cylinder and are connected with wings 3, 4 of ring-like shape at its both ends. Four of guard rings 6, 7, 8, 9 are placed on both inner and exterior sides of the wing 3 and 4. Owing to the guard rings, electric field waves are distributed in the minimized space. Thus, dielectric loss can be minimized and examination results with a high S/N ratio can be obtained. As mutural interferences caused by electromagnetic connection are little, no noises are induced. Furthermore, since there is no heat-generation risk, examination can be safely practiced.