Abstract: A novel type of skeleton for polygonal figures is introduced and discussed. The new skeleton is based on the straight skeleton, but it is more precise than the straight skeleton in shape description because the strictly-parallel wave front of the straight skeleton is replaced by a rounded one which is close to that of the medial axis. Moreover, it is simpler than the medial axis in structure because it is only composed of linear segments and one kind of elements. The algorithm for this new type of skeleton is also presented. A preprocessing module which converts a reflex vertex into several vertices is added into the original straight skeleton algorithm. These vertices have the same position as the reflex vertex, but they have different propagation directions which make them form an arc after some distance. The special collision problem is taken into account to improve the robustness also. Experiments show that the algorithm is robust and efficient.