A method for designing a coil pattern, whereby the production of an error magnetic field and further an eddy current can be suppressed to improve the quality of a cross-sectional image irrespective of cylindrical cross-sectional shape of the main coil and the shield coil. The difference between the initial values of the target magnetic field and the magnetic field vector is set as a difference target magnetic field. An approximate value of the current potential vector that produces the difference target magnetic field is represented by a polynomial of an eigenvector group of the current potential. The coefficient of each of the terms of the polynomial is determined on the basis of the singular value and the eigenvector group of the magnetic field distribution.