The present invention provides a spoken document retrieval system capable of high-speed and high-accuracy retrieval of where a user-specified keyword is uttered from spoken documents, even if the spoken documents are large in amount. Candidate periods are narrowed down in advance on the basis of a sequence of subwords generated from a keyword, and then the count values of the candidate periods containing the subwords are each calculated by adding up certain values. Through such simple process, the candidate periods are prioritized and then selected as retrieved results. In addition, the sequence of subwords generated from the keyword is complemented assuming that speech recognition errors occur, and then, candidate period generation and selection are performed on the basis of the complemented sequence of subwords.