A radio tomographic image generation device includes a reconstruction unit for generating a plurality of reconstructed images of different iteration numbers by a successive approximation process; a region segmentation unit for obtaining information about structure based on radiographic image signals, and segmenting, based on the information about structure, a region, of which the tomographic image is generated, into a plurality of segmented regions having different information about structure; and an image combining unit for generating partial tomographic images by using the reconstructed images of different iteration numbers for the individual segmented regions based on the information about structure of the individual segmented regions, and generating a tomographic image of a subject by using the generated partial tomographic images for the individual segmented regions.