Provided is an open-type MRI apparatus comprising a pair of magnetic field generating means arranged to face each other across a space for imaging an object, a pair of static magnetic field generating means holding means for holding the pair of static magnetic field generating means at a predetermined interval, and a pair of tabular gradient magnetic coil structures arranged on the imaging space side of the static magnetic field generating means. The individual tabular gradient magnetic coil structures are fixed on their individually facing static magnetic field generating means at a plurality of positions for suppressing the deformations, which occur in the gradient magnetic coil structures, by the Lorentz forces which act, when driving electric currents are fed to gradient magnetic coils, on the coil conductors.