1. A magnetic resonance imaging system for interventional MRI involving an operator's operation to insert a catheter into an object, the catheter having a tip and being inserted into the object from the tip thereof, comprising: scanning means for magnetically scanning a region of the object to acquire image data of the region; detection means for detecting positional information indicative of a position of the tip of the catheter within the object; tracking means for automatically tracking an imaging section which changes according to a motion of the catheter when a traveling direction of the catheter is changed; and display means for displaying both of an image based on the acquired image data of the region and, together with the image, a movement state of the tip of the catheter based on the detected positional information; wherein the display means is configured to display, in a superimposition manner, the positional information of the position of the tip on the image serving as a reference image, and to display the imaging section which tracks the motion of the catheter when the traveling direction of the catheter is changed.