PURPOSE: To obtain a highly accurate NMR shimming device which can by manufactured easily.

CONSTITUTION: The title item is provided with a compensation coil 2-i (i=1-N) with each one turn which is wound while surrounding a sample space 1 and a reference voltage part 5 consisting of N×4 pieces voltage sources where four types of voltage values correspond to each compensation coil and four types of voltage values satisfies the relationship of m-order function (m=1-4) in the relationship with the winding position of the compensation coil. Furthermore, it is provided with voltage addition parts 4-i and 6-im which receive four types of voltages V1(i)-V4(i) and a common voltage G0V0 and then perform addition according to specified ratios G0-G4, a current conversion part 3-i which receives the output voltages of the voltage addition parts 4-i and 6-im and then supplies current which is proportional to them, and a ratio setting part for setting the above addition ratios G0-G4 in the voltage addition parts 4-i and 6-im.