A magnetic resonance imaging apparatus includes control means 107 and 108 for continuously performing magnetic resonance imaging of a cross section including a portion subjected to measurement of an examinee (101) at a predetermined time interval, operation means 108 for calculating diagnosis information related to the portion subjected to measurement by using a plurality of sets of nuclear magnetic resonance signals related to cross sections imaged at different time points by measuring nuclear magnetic resonance signals generated from the examinee 101, and a position detection device 118 having a detection camera 118b for detecting in non-contact manner the position (three-dimensional position and rotation angle around an orthogonal coordinate axis) of a pointer 118a provided outside the examines body and moving while interlocked with the biological movement of the examinee 101. The control means 108 sets the position of the cross section according to the position of the pointer 118a detected by the position detection device 118, thereby eliminating an affect of the biological movement and improving the accuracy and the reliability of the diagnosis information including differential processing of a portion subjected to measurement.