A specific area detection device that detects a specific area in an imaging area based on a captured image includes: an estimation unit configured to estimate a plurality of points and a direction of a straight line connecting two predetermined points among the plurality of points from a captured image using a learning model created by learning about a specific area defined by a predetermined number of the points in an imaging area using a captured image for learning; and a detection unit configured to detect the specific area by classifying the plurality of points for each specific area based on the direction.