For the purpose of making available an RF coil which makes possible a reduction in elements to be controlled in varying the size of the RF coil, there are provided an original loop unit, a conductor so connected to the original loop unit as to split the original loop unit into split loop units, a capacitor connected in series to the conductor, and switching means which makes the conductor either conductive or non-conductive, wherein the electrostatic capacitance of the capacitor is so set as not to allow the split loop units to interfere with each other when the conductor is made conductive by the switching means.