1. A video recording apparatus comprising: a content accumulation part accumulating video content; a feature extraction processing part extracting an image or voice as a feature from the video content accumulated by the content accumulation part, and obtaining word information from the extracted image or the extracted voice; a word information acquisition part acquiring sorted word information obtained using clustering processing on word information identified from an image captured by a camera; and a content retrieval part retrieving relevant video content from the video content accumulated by the content accumulation part based on a similarity determination involving word comparison involving the sorted word information acquired by the word information acquisition part and the word information acquired by the feature extraction processing part, the word information obtained from the feature extraction processing part includes information of a number of words and information regarding a class associated with each word within a hierarchical class arrangement, in which a lower class word is assigned a higher weight than a higher class word, so that in the word comparison of the similarity determination performed by the content retrieval part a successful word comparison involving a respective low class word is considered as having a higher similarity as compared to a successful word comparison involving a respective high class word.
4. The video recording apparatus according to claim 1 , wherein the word information acquisition part acquires the sorted word information obtained using the clustering processing on word information acquired by character recognition processing on the image captured by the camera.