1. A magnetic resonance imaging apparatus comprising: a sensitivity map database that stores sensitivity map data of a multi-coil including plural coils for parallel imaging unfolding processing; a data slice unit that slices partial data from three-dimensional volume data collected for the respective coils by parallel imaging, respectively; an intermediate image reconstruction unit that reconstructs intermediate images from the partial data; and a reference image generation unit that slices sensitivity map data corresponding to the intermediate images from the sensitivity map database, executes the parallel imaging unfolding processing for the intermediate images using the sensitivity map data, and generates reference images.