An image capturing section captures a face of an observed person. A position detecting section detects, from a face image expressing the face captured by the image capturing section, one of a position expressing a characteristic of a nose and a position expressing a characteristic of a region between eyebrows. A computing section computes a past relative position of a predetermined region of the face that is based on the position detected in the past by the position detecting section. A region position detecting section detects a position of the predetermined region on the basis of the past relative position computed by the computing section and the current position detected by the position detecting section.
Face region detecting device, method, and computer readable recording medium