A mobile entity detection apparatus for detecting a mobile entity from image data output by an imaging device installed in a vehicle, the detection apparatus comprising: a feature point extraction unit configured to calculate an unbiased variance of luminance change using image data for a predetermined number of frames and compare the calculated value with a threshold value to determine whether each pixel on the latest image data corresponds to a moving pixel or a stationary pixel, set an area in which a pixel determined to be a moving pixel exists as a movement area in which a mobile entity exists, extract feature points in the movement area of the image data of the latest image data using a FAST algorithm; an optical flow specification unit configured to compare the latest image data with image data that was output further in the past, and specify an optical flow for each feature point extracted; a clustering unit configured to perform clustering on the optical flow based on the specified optical flow and the position of the specified optical flow in the image, and separate the optical flow into a plurality of clusters; a tracking unit configured to determine, for each cluster obtained by clustering, whether or not the position of each cluster overlaps a position of a cluster determined from image data other than the latest image data, by the clustering unit; wherein clusters determined to overlap are output; a filtering unit configured to remove a cluster that corresponds to an object forming a background from among clusters obtained by the tracking unit, based on the traveling direction and speed of the vehicle; and a mobile entity specification unit configured to specify a mobile entity in the image using a result of clustering after cluster removal by the filtering unit. calculate an unbiased variance of luminance change using image data for a predetermined number of frames and compare the calculated value with a threshold value to determine whether each pixel on the latest image data corresponds to a moving pixel or a stationary pixel, set an area in which a pixel determined to be a moving pixel exists as a movement area in which a mobile entity exists, extract feature points in the movement area of the image data of the latest image data using a FAST algorithm; an optical flow specification unit configured to compare the latest image data with image data that was output further in the past, and specify an optical flow for each feature point extracted; a clustering unit configured to perform clustering on the optical flow based on the specified optical flow and the position of the specified optical flow in the image, and separate the optical flow into a plurality of clusters; a tracking unit configured to determine, for each cluster obtained by clustering, whether or not the position of each cluster overlaps a position of a cluster determined from image data other than the latest image data, by the clustering unit; wherein clusters determined to overlap are output; a filtering unit configured to remove a cluster that corresponds to an object forming a background from among clusters obtained by the tracking unit, based on the traveling direction and speed of the vehicle; and a mobile entity specification unit configured to specify a mobile entity in the image using a result of clustering after cluster removal by the filtering unit.