Several methods have been proposed for compressing the linkage data of a Web graph. Among them, the method proposed by Boldi and Vigna is known as the most efficient one. In the paper, we propose a new method to compress a Web graph. Our method is more efficient than theirs with respect to the size of the compressed data. For example, our method needs only 1.99bits per link to compress a Web graph containing 3, 216, 152 links connecting 325, 557 pages, while the method of Boldi and Vigna needs 2.84bits per link to compress the same Web graph.