1. An image diagnostic processing device, comprising: peripheral region specifying means for specifying a peripheral region connecting to an abnormal candidate region included in an image representing an inside of a subject; and judging means for using a segment which passes through the abnormal candidate region and the peripheral region as an observation line and for judging whether the abnormal candidate region is an anatomic abnormal region or not, based on variation between a first feature quantity obtained in relation to a plurality of observation points located on the observation line in the abnormal candidate region and a second feature quantity obtained in relation to the plurality of observation points located on a reference line in the peripheral region.