A magnetic resonance imaging apparatus comprises a collecting section that collects from the subject the magnetic resonance signals corresponding to N phase encode data items for restructuring each of a plurality of images, a restructuring section that restructures each set of N phase encode data items corresponding to the magnetic resonance signals obtained by the collecting section, an image processing section that processes the restructured images obtained at the restructuring section, an image output section that outputs the processed images obtained at the image processing section, and a changing section that changes the number of phase encode data items updated among the N phase encode data items restructured at the restructuring section, while the collecting section is in operation.