To suppress the image quality deterioration due to respiratory motion and changes thereof, and improve the data acquisition rate. An MRI device according to the present invention repeats a main measurement in a predetermined unit, and performs a navigation measurement to acquire one or a plurality of the navigator echoes between the measurements in the temporally adjacent two predetermined units, and performs determination as to whether to continue or discontinue the main measurement and determination as to whether to discard immediately prior measurement data. In the determination, at least two navigator echoes are used, and by using a position of a site to be monitored by the navigation measurement and a displacement width serving as a reference of the displacement stability, whether the position and the displacement width satisfy a reference displacement and a reference displacement width, which have been obtained in advance, is determined.