Conventional coating tools have a high affinity for ductile materials, like aluminum alloy, so cutting chips tend to adhere to cutting edge and work material surface. Therefore, chipping is caused, and surface texture is degraded. In order to solve these problems, recently, DLC (Diamond-Like-Carbon) has been applied to coating material. In this research, it is curried out cutting of Aluminum alloy by the use of DLC coating tool, and examined influence of DLC coating conditions on cutting characteristics. So far we have been concerned with the effect of type of hydrocarbon gas (acethylene:C2H2, methane:CH4) on cutting. As a result, it is revealed that cohesion of chips decreases, and surface roughness of work material improves in the case of acethylene-DLC. On the other hand, internal stress is produced by deference in hardness between tool surface and DLC film, and which is considered cause of film peeling . Therefore, we examined interlayer between DLC film and tool surface in order to relax of internal stress. As a result, it was cleared that Titanium interlayer excels in adhesion.