1. A magnetic resonance imaging apparatus comprising: a pulse sequence generating unit which repeatedly generates a data acquisition pulse sequence based on the same phase encoding pattern at least twice; a magnetic field generating unit which generates a gradient field on the basis of the data acquisition pulse sequence and applies the gradient field to a subject to be examined; a magnetic field generating unit which generates an RF field on the basis of the data acquisition pulse sequence and applies the RF field to the subject; a data acquiring unit which acquires magnetic resonance data on the basis of a magnetic resonance signal generated in the subject; a heartbeat information acquiring unit which acquires heartbeat information of the subject; an extracting unit which extracts partial magnetic resonance data from the magnetic resonance data on the basis of the acquired heartbeat information; and a reconstructing unit which reconstructs an image by using the extracted partial magnetic resonance data.