An RF coil includes a plurality of concentric loops lying at different
positions along a coil axis, whose sensitivity is improved in a central
portion, and a plurality of loops are constructed as circular loops whose
circles correspond to those formed by cutting a sphere common to the
loops vertically with respect to the coil axis at different positions
along the coil axis. Each of the plurality of loops constitutes a
solenoid coil. Alternatively, a helical coil uninterruptedly running
around the coil axis is formed.
