1. A magnetic resonance imaging apparatus for generating an image related to a radiographing area of a subject on the basis of a magnetic resonance signal produced in the radiographing area within a static magnetic field space, the magnetic resonance imaging apparatus comprising: a fiber tracking device for tracking a running fiber in the radiographing area on the basis of a diffusion tensor calculated from the magnetic resonance signal; and a diffusion tensor color map image generating device for generating as said image a diffusion tensor color map image so as to match a curved surface including a tract extracted in the fiber tracked by the fiber tracking device, wherein the diffusion tensor color map image generating device generates the diffusion tensor color map image in such a manner that, in the fiber tracked by the fiber tracking device, pixels corresponding to the fiber running as the tract along the curved surface are made equal in color, and the pixels corresponding to the fiber running as the tract along the curved surface and pixels corresponding to a fiber running as a fiber other than the tract in a direction different from the tract become different in color.