PURPOSE: To collect magnetic resonance signals without being affected by the number of respiration and respiration amplitude of a patient by detecting an inhalation state and an exhalation state, determining correction time in accordance with the repeating time of respiration waveforms and adding the correction time to the level signals of the inhalation and exhalation states.

CONSTITUTION: A computer 7 controls a high-frequency magnetic field generator 4, a ramp magnetic field power source 3 and a ramp magnetic field coil 2 in accordance with taking-in sequence when encode processing is executed. The spin of the desired section of the testee body 10 is excited by a high-frequency signal receiving coil 9. The computer 7 takes in an echo signal via a signal receiver 5 and a data taking in section 6 when the echo signal is generated by the spin excitation. These operations are repeated by as mush as a set number of integration times and the resulted signals are subjected to image reconstitution to form the image which is displayed on a display device 8. A method for detecting the period of the smallest motion can be programmed by a ROM circuit, etc.