In NMR system, for preventing a temperature gradient which causes a decrease in S/N ratio from being created in a sample area while suppressing deterioration in homogeneity of a magnetic field, a thermal conductor having high thermal conductivity is disposed in a room-temperature shim coil. The thermal conductor is provided as a coil bobbin, the temperature of the thermal conductor being controlled by a temperature controller using a heat exchanger. Temperature control gas, which is adjusted to a temperature equal to that of the room-temperature shim coil, is fed from the downside of a sample tube, and it is possible to suppress a temperature gradient from being created in a sample area. According to the present invention, since the temperature distribution can be made to be uniform so as to avoid creating a temperature gradient in the sample area while suppressing deterioration of homogeneity in the magnetic field, the NMR spectrum is sharpened so as to improve the S/N ratio.