Magnetic resonance imaging apparatus of the present invention includes a static magnetic field generating unit for applying a static magnetic field in the imaging space, and a high frequency magnetic field generating unit than the static magnetic field generating unit disposed in the imaging space side, of the high-frequency magnetic field generating unit and the imaging space is disposed between, and the bore wall to form a space that is disposed object, the temperature of the bore wall and a determining temperature determining unit whether it exceeds a predetermined temperature, the temperature determination unit includes a thermistor, And a detection circuit connected to the thermistor for obtaining a voltage signal corresponding to the electric resistance value of the thermistor and determining a voltage signal, wherein the detection circuit includes a determination circuit having a hysteresis characteristic, and the determination circuit includes a bore wall temperature increases, the voltage signal, when it reaches the voltage value of the high temperature side than the voltage value corresponding to a first temperature, and determines an abnormal state exceeding the predetermined temperature, then the temperature of the bore wall is lowered , lower than the first temperature If than the voltage value corresponding to the second temperature reaches a voltage value of the low temperature side, and judging the following normal state predetermined temperature.本発明の磁気共鳴イメージング装置は、撮像空間に静磁場を印加する静磁場発生部と、静磁場発生部よりも撮像空間側に配置された高周波磁場発生部と、高周波磁場発生部と撮像空間の間に配置され、被検体が配置される空間を形成するボア壁と、ボア壁の温度が所定温度を超えているかどうかを判定する温度判定部とを有し、温度判定部は、サーミスタと、サーミスタに接続され、サーミスタの電気抵抗値に対応した電圧信号を得て、電圧信号の判定を行う検出回路とを含み、検出回路は、ヒステリシス特性をもつ判定回路を備え、判定回路は、ボア壁の温度が上昇し、電圧信号が、第1の温度に対応する電圧値より高温側の電圧値に到達した場合は、所定温度を超えた異常状態と判定し、その後ボア壁の温度が下降し、第1の温度よりも低温の第2の温度に対応する電圧値よりも低温側の電圧値に達したならば、所定温度以下の正常状態と判定することを特徴とする。
