PURPOSE: To correct a sensitivity in hardware way by setting frequency characteristics of a low-pass filter in a receiving circuit to a reciprocal of sensitivity characteristics of an RF coil.

CONSTITUTION: A specified nucleus of a body 1 to be inspected is excited by impression of an RF magnetic field generated by a static magnetic field Ho and the RF coil 2. A nuclear magnetic resonance signal generated after releasing the RF magnetic field is detected by a tuner 3, an amplifier 5 and inputted to two phase detectors 6A, 6B. The detectors 6A, 6B detect the resonance signal in quadrature phase basing on two kinds of reference waves from a reference signal generator 7 and input the resonance signal to the low-pass filters 9A, 9B. These low-pass filters have functions for removing the high frequency portion and correcting the sensitivity distribution. Namely, the filters 9A, 9B have the inversed frequency characteristics against the sensitivity characteristics of the RF coil. Thereby, the constitution of the data processing unit can be simplified compared with one performing the correction in software way.