To provide a robot system equipped with an off-line programming device which can create a machining path consisting of a trajectory of any shape, and can reduce the workload required in teaching of the machining path of any shape. Provided is an off-line programming device which teaches a program of a robot equipped with a toll that machines a workpiece arranged within a work space, the off-line programming device including a trajectory information creation unit which creates trajectory information of any 3D shape consisting of at least one layer; and a trajectory information editing unit which edits line segments constituting the trajectory information of the any 3D shape consisting of at least one layer.