Abstract: An apparatus for generating a corrective magnetic field in a nuclear magnetic resonance (NMR) spectrometer. The apparatus has saddle-type, spirally wound coils whose number is in excess of the number of controlled magnetic field components. Each coil is made to produce plural magnetic field components. The coils of a simple shape are combined to correct axial magnetic field components and rotation direction magnetic field components. Electrical currents supplied to the coils are controlled so as to minimize the total amount of heat generated by all the coils. The center of each coil lies on the z-axis. The coils are stacked on top of each other along the z-axis and arranged symmetrically with respect to the z-axis. One power supply is connected to each one coil. Since the number of the coils is greater than the number of controlled magnetic field components, other arbitrary conditions are added, as well as the controlled magnetic field-components, in determining the currents.