1. A visual attention detector configured to predict a region in a video likely to attract visual attention, the visual attention detector comprising: a feature extraction unit configured to extract a spatiotemporal feature from a local region in a video, a spatiotemporal feature representing a spatial and a temporal change in an image in the local region; a hashing unit configured to convert a spatiotemporal feature value for the local region into a hash value using a hash function, and to select a training value mapped to the hash value for the local region using a hash table wherein a training value learned in advance for a spatiotemporal feature is registered in a bucket mapped to a hash value; and an attention measure determining unit configured to determine an attention measure for the local region on the basis of the distance between a spatiotemporal feature value for the local region and the selected training value such that the larger the distance the larger the attention measure.