A magnetic resonance imaging apparatus comprises a plurality of high-frequency reception coils, sensitivity distribution information obtaining means for calculating sensitivity distribution information of each of the high-frequency reception coil, sensitivity distribution storage means for storing the sensitivity distribution information, measuring means for acquiring magnetic resonance signals by thinning out encode steps of a k-space, image reconstructing means for reconstructing images using the magnetic resonance signals, and means for performing unfolding calculation using the sensitivity distribution information and the image, thereby to acquire the unfolded image. The magnetic resonance imaging apparatus further comprises means for estimating the sensitivity distribution information of a background region by using the sensitivity distribution information of an object region, and means for updating the background region by mutually using the sensitivity distribution information of the respective high-frequency receptions coils thereby to suppress noise component contained in the unfolded image.