In this paper, we present a new coding scheme for depth maps using a hierarchical decomposition. After we decompose a depth map into three disjoint images and a layer descriptor according to the region of edges, we merge the disjoint images of each depth map into an image. Then, the merged images and the layer descriptor are coded by H.264/AVC. Unlike previous mesh-based depth coding methods, we compress the irregular depth information using a conventional 2D video coder. Experimental results show that our scheme improves compression efficiency of meshbased depth coding.