An RF coil having at least three different resonance frequencies, wherein one of the resonance frequencies is adjusted to be a frequency f.sub.A of a magnetic resonance signal generated by a test subject, and the coil is adjusted so that ratio of difference between the frequency f.sub.A and a first frequency f.sub.B lower than f.sub.A and nearest to f.sub.A among the resonance frequencies (f.sub.A-f.sub.B), and difference between the frequency f.sub.A and a second resonance frequency f.sub.C higher than f.sub.A and nearest to the frequency f.sub.A among the resonance frequencies(f.sub.C-f.sub.A), should be from 0.5 to 2.0. There is provided a technique for receiving magnetic resonance signals always with high detection efficiency by an RF coil of an MRI apparatus even if significant loss is caused in the RF coil, or test subject is changed.