Provided is a preview image generating section configured to generate preview image during radiography for the purpose of providing a radiation tomography apparatus that allows suppression of unnecessary imaging time by displaying a condition of an image during the radiography in the process of diagnosis. An operator can recognize from the preview image how a subject appears in the image in a radiation tomography apparatus also during the radiography. This allows stopping the radiography before a diagnostic image having a suitable level of clearness for diagnosis is generated. As a result, a shorter imaging time is achieved, and burden to the subject can be suppressed.
