The present invention provides an image reconstruction apparatus and an image reconstruction method, both of which achieve reduction in a granular noise and a streak-like artifact both contained in a reconstruction image, and a clear structure boundary as well The image reconstruction apparatus configured to generate a reconstruction image includes a noise reduction section that generates a streak reduction image as an image obtained by reducing a streak-like artifact in the reconstruction image, a noise reduction ratio acquisition section that acquires a first noise reduction ratio as a noise reduction ratio to be used for reducing a granular noise while retaining a structure boundary in the reconstruction image, and a second noise reduction ratio as a noise reduction ratio to be used for generating the streak reduction image, and an image addition section that adds an addition image to be generated based on the first noise reduction ratio and the second noise reduction ratio to the streak reduction image.
