An ophthalmologic apparatus comprising: a front image acquiring device configured to acquire a front image of a fundus of a subject's eye, the front image being a frame of an observation image obtained by motion-picture photography using near infrared light; a search processor designated in the following as first search processor configured to search for an interested region corresponding to an interested site of the fundus based on a brightness variation in the frame of the observation image; a further search processor designated in the following as second search processor configured to search for said interested region by template matching between the frame of the observation image and a template image in the event that said interested region has not been detected by the first search processor; and a further search processor designated in the following as third search processor configured to detect a blood vessel region corresponding to a blood vessel of the fundus by analyzing the frame of the observation image and search for said interested region based on a distribution of the blood vessel region in the event that said interested region has not been detected by the second search processor; wherein the front image acquiring device is configured to acquire another front image of the fundus acquired using a modality different from a modality used for acquisition of the frame of the observation image, the another front image being an optical coherence tomography angiogram acquired using OCT angiography different from the motion-picture photography, and the third search processor is configured to detect the blood vessel region corresponding to the blood vessel of the fundus by: detecting a first blood vessel region corresponding to the blood vessel of the fundus by analyzing the OCT angiogram; performing registration between the frame of the observation image and the OCT angiogram; and identifying, as the blood vessel region, a second blood vessel region of the frame of the observation image corresponding to the first blood vessel region based on a result of the registration, and the third search processor is further configured to search for said interested region based on a distribution of the second blood vessel region. a front image acquiring device configured to acquire a front image of a fundus of a subject's eye, the front image being a frame of an observation image obtained by motion-picture photography using near infrared light; a search processor designated in the following as first search processor configured to search for an interested region corresponding to an interested site of the fundus based on a brightness variation in the frame of the observation image; a further search processor designated in the following as second search processor configured to search for said interested region by template matching between the frame of the observation image and a template image in the event that said interested region has not been detected by the first search processor; and a further search processor designated in the following as third search processor configured to detect a blood vessel region corresponding to a blood vessel of the fundus by analyzing the frame of the observation image and search for said interested region based on a distribution of the blood vessel region in the event that said interested region has not been detected by the second search processor; the front image acquiring device is configured to acquire another front image of the fundus acquired using a modality different from a modality used for acquisition of the frame of the observation image, the another front image being an optical coherence tomography angiogram acquired using OCT angiography different from the motion-picture photography, and the third search processor is configured to detect the blood vessel region corresponding to the blood vessel of the fundus by: detecting a first blood vessel region corresponding to the blood vessel of the fundus by analyzing the OCT angiogram; performing registration between the frame of the observation image and the OCT angiogram; and identifying, as the blood vessel region, a second blood vessel region of the frame of the observation image corresponding to the first blood vessel region based on a result of the registration, and the third search processor is further configured to search for said interested region based on a distribution of the second blood vessel region.