An abnormality detection apparatus including a feature extraction circuit configured to extract a feature point and a feature value of a first image, and a feature point and a feature value of a second image, a flow calculation circuit configured to calculate, based on the feature value of the first image, a first abnormality detection circuit configured to detect an abnormality in the first image based on a first optical flow, and to detect an abnormality in the second image based on a third optical flow, and a second abnormality detection circuit configured to detect an abnormality in the first or second image based on a result of a comparison between the second optical flow and a fourth optical flow.