In order to provide a high intensity magnetic field open type MRI apparatus which suppresses electro-magnetic interference to super-conducting coils due to gradient magnetic field coils and high frequency magnetic field coils and to realize stable operation of super-conducting magnet, in a static magnetic field generating magnet 102, a pair of cryostats 117 are connected by a coupling tube 201 and disposed in vertical direction while sandwiching a space 118 where a subject is laid, and in vessels 202 and 203 filled with liquid helium in the respective cryostats super-conducting coils are accommodated. To the cryostats 117 an emergency demagnetizing unit 120 for attenuating magnetic field and a measurement unit 121 for monitoring helium liquid level belong, and signal cables therefor are connected to an inner circuit of the static magnetic field generating magnet 102 via a filter circuit 122. High frequency current induced when the gradient magnetic field coils and the high frequency magnetic field coils are driven is interrupted by the filter circuit 122 and is caused to flow to a connection point 123 via the outer casing of the cryostats 117, thereby, no influences are effected to the inner circuit in the cryostats 117.