Insight into the machining mechanism, crack creation and the chip formation in metal vibratory cutting has yet to be carried out for this technique to be used widely and efficiently. The large-scale FEM soft ware, ANSYS, is utilized for the crack creation process and for the quantitative analysis. Contrast and comparison experiments between vibratory and the conventional metal machining is done, revealing a good agreement between the simulation and the experiment and the inborn nature and the principles of the vibratory metal cutting. The fracture impact resistance in the crack tip zone becomes much lower than that in conventional cutting, other conditions being equal. In this case smaller force is required to have deformed the metal plastically and make the fracture occur. Results will be used for the aspects of the basis for workshop operation.