A reconstruction processing method. The method includes an image updating step (Step S2) of updating a reconstruction image by an iterative approximation method, and a weighting coefficient map updating step (Step S4). In the weighting coefficient map updating step, a weighting coefficient map relative to prior knowledge is generated from the reconstruction image obtained by updating an image in the image updating step (Step S2), and a weighting coefficient of the prior knowledge relative to each pixel is controlled in accordance with the weighting coefficient map, whereby a weighting coefficient map is updated. As described above, the weighting coefficient map relative to the prior knowledge is generated from the reconstruction image (during estimation) obtained by updating the image, and the weighting coefficient of the prior knowledge relative to each pixel is controlled in accordance with the weighting coefficient map.