An off-line programming system (10) which includes a three-dimensional shape arranging unit (27) which fills in a curved surface or consecutive plurality of flat surfaces of a selected three-dimensional shape by selected operation patterns and arranges a three-dimensional shape in a virtual space so that the operation patterns will be projected on surfaces of the workpiece model, a working path preparing unit (28) which projects operation patterns on the surfaces of the workpiece model so as to prepare a working path of the tool, and a tool position/posture determining unit (29) which uses the prepared working path and normal direction of the surface of the workpiece model as the basis to automatically determined the position or position/posture of the tool model.