Recently, many types of robotic bending system have been introduced in sheet metal industry, and a dual-arm robotic system is one of the most expected systems for flexible bending system. In this study, a planning of regrasp motion of a sheet metal is proposed. The regrasp motion is the most characteristic advantage of a dual-arm robotic system. Since, the path of regrasp motion is decided in free space with less geometric restriction, a graph searching approach is applied in order to find the shortest way between start and goal nodes. The graph is constructed whose nodes are consisted of the configuration of a sheet metal, the grasping position on the sheet metal and posture of the arms. The shortest path is obtained by Dijkstra's method and the motion of arms is decided based on the path obtained. The proposed method is coded in a computer program and effectiveness of the method is evaluated by computer simulation with many sheet metal examples.