The invention belongs to the petroleum gas exploration field and relates to a nuclear magnetic resonance device and a logging instrument thereof. According to the nuclear magnetic resonance device andthe logging instrument thereof of the invention, the frequency of a radio frequency oscillator in the nuclear magnetic resonance device is increased, so that the strength of a magnetic field can be increased; and it is ensured that an applied magnetic field and a static magnetic field which is generated by magnets are equal in strength and are perpendicular to each other in direction. With the nuclear magnetic resonance device and the logging instrument thereof of the invention adopted, the inspection result of a drilling fluid to be tested is more accurate, and an important basis is providedfor oil and gas discovery and reservoir fluid evaluation.