There are many useful documents for various educational subjects on the WWW. The demand for reusing web documents is increasing in the pedagogical domain. In this paper, a component approach to reuse web documents is proposed. This approach is achieved through two basic methods. One is a decomposition method, which decomposes a web document into separate description units. Another is a selection method, which selects some of those units and reconstructs a document with them. Utilizing those two methods together, one is able to reuse a part of the original web document as an instructional material component. This component approach based on the above two methods facilitates the reuse of web documents in the pedagogical domain.