To highly accurately calculate high resolution coil sensitivity distribution independent of the shape and structure of a subject.SOLUTION: An MRI apparatus comprises: a measuring unit which comprises a receiving coil composed of a plurality of channels and measures a nuclear magnetic resonance signal of a subject for each channel of the receiving coil； and an image calculation unit which uses a sensitivity distribution for each channel of the receiving coil and a channel image obtained from the nuclear magnetic resonance signal for each channel measured by the measurement unit to create an image of the subject. The image calculation unit comprises a sensitivity distribution calculating unit that uses the channel image and a composite image obtained by compositing the channel image to calculate a sensitivity distribution on a space k for each channel.SELECTED DRAWING: Figure 9【課題】被検体の形状や構造に依存しない高解像度コイル感度分布を高精度に算出する。【解決手段】ＭＲＩ装置は、複数のチャンネルからなる受信コイルを備え、前記受信コイルのチャンネル毎に被検体の核磁気共鳴信号を計測する計測部と、前記受信コイルのチャンネル毎の感度分布と、前記計測部が計測したチャンネル毎の核磁気共鳴信号から得たチャンネル画像とを用いて前記被検体の画像を作成する画像演算部と、を備え、前記画像演算部は、前記チャンネル画像と当該チャンネル画像を合成した合成画像とを用いて、チャンネル毎に、ｋ空間上で感度分布を算出する感度分布算出部を備える。【選択図】図９
