PURPOSE: To stably provide a diffusion image always at a heartbeat time phase with least artifact even if the heartbeat period of a human body is unstable by executing a diffusion preparation portion preceded by a gradient preparation portion, then executing a high-speed FE sequence.

CONSTITUTION: A principal magnet 11 has a Gz coil 12, a Gy coil 13 and a Gx coil 14 disposed therein to generate inclined magnetic fields Gx, Gy, Gz. An exciting RF pulse is fed from a transmission power amplifier 26 to a transmitting antenna attached to an examinee and a receiving antenna receives an NMR signal and feeds it to a computer 20. The output of an electrocardiograph 31 is transmitted to the computer 20 and constantly monitored, and the computer 20 then controls the waveform of each inclined magnetic field and its timing and the waveform of the RF pulse and its timing and executes a predetermined pulse sequence by setting the frequency of the RF pulse to a resonance frequency by control of a signal generator 23.