1. A program search apparatus, comprising: a program information storage unit storing program information; an operation history storage unit storing TV operation history; a preference information management unit generating preference information from the program information and the TV operation history and for managing the preference information at prescribed periods; and a preference change amount calculation unit calculating an amount of change of the preference information managed at prescribed periods; and the apparatus generates a search request with a weight adjusted according to the amount of change of the preference information, and searches a recommended program from the program information on the basis of the search request.