Provided are an image processing apparatus and an image processing method that can suitably broaden a field of view. The image processing apparatus includes: first input means for receiving input of sinogram information acquired by projecting radiation onto an object； means for configuring a first tomographic image of the object from the sinogram information； second input means for receiving input of a prior tomographic image obtained by imaging the object before the sinogram information； conversion means for converting a pixel value of the prior tomographic image on the basis of a pixel value of the first tomographic image； and means for generating a second tomographic image from the sinogram information with use of the prior tomographic image, the pixel value of which has been converted.
