To provide an X-ray CT apparatus and an image reconstruction method that can generate an image in which motion influence of a site to be scanned is reduced, the image processing device 403 of the X-ray CT apparatus 1 calculates a reconstruction data range which is a range of projection data to be used for reconstruction based on a motion direction of the site to be scanned. An image is reconstructed using the projection data in the calculated reconstruction data range. The reconstruction data range is set as the projection data in a projection range of at least 180 degrees or more including a projection direction that approximately corresponding to the motion direction of the site to be scanned.