[en] Development of a superconducting magnet system for the 8 mm gyrotrone tube is discribed in this paper. Magnetic field at the axis of its main field coil has reached 2.14 T. Length of uniform region is 14.5 cm Degree of uniformity is ±3.84per mille. It could be operated in persistent mode by means of superconducting switch. Length of uniform region of the secondary field coil is 4.5 cm. Degree of uniformity is ±1.43per mille. Dewar vessel has a home temperature bore in step mode. The upper section diameter is 74 mm and the lower section is 140 mm. The average liquid helium boil-off rate of dewar vessel with superconducting magnet is 4 L/h