1. A magnetic resonance imaging apparatus comprising: a sensitivity map data generating unit configured to generate reference image data based on data for generating sensitivity map data of a phased array coil and generate the sensitivity map data by using reference image data after correction processing obtained by applying the correction processing to improve a uniformity with the reference image data based on the reference image data and phased array coil data for generating the sensitivity map data, the data being acquired from an object, the phased array coil data being acquired with the phased array coil as a receive coil; and a sensitivity corrected image data generating unit configured to acquire image data for imaging from the object with the phased array coil as a receive coil and generate image data after sensitivity correction by performing the sensitivity correction of the image data using the sensitivity map data.