In an MRI apparatus, an RF coil is provided which can generate or detect a circularly-polarized magnetic field with one feeding port, and which can radiate highly efficient, highly homogeneous electromagnetic waves and detect a highly sensitive, highly homogeneous magnetic resonance signal. For this purpose, the coil has a cylindrical shape, one feeding port which exchanges signals, plural first capacitors disposed at circumferential positions in at least one cross-section effectively orthogonal to the direction of the static magnetic field, and at least one second capacitor. In this RF coil, in which a static magnetic field is applied in essentially an identical direction to the direction of the central axis of the cylindrical shape, a second capacitor having a smaller capacity than the capacity of the first capacitor, is disposed at a position from 22.5.degree. to 67.5.degree. or 202.5.degree. to 247.5.degree. in a clockwise direction with respect to the center of the cylindrical shape from the feeding port in a cross-section viewed from a direction passing through the static magnetic field.