A Y-shape filtered-arc-deposition system, which has two arc sources and a common plasma-transport-duct, was operated under nitrogen gas, and a titanium aluminum nitride (TiAlN) thin film was prepared with Ti and Al cathodes. Two filtered-arc plasma beams were not completely combined into one beam even at the exit of the common duct. Thus, TiAlN film with composition-uniform distribution was not obtained at the fixed substrate position. However, different composition films were easily obtained at one time. Then various-composition films of TiAlN with different arc currents were prepared and film properties were measured. The surface roughness in arithmetical mean roughness was less than 3 run on a 1.5-nm roughness substrate. The density of TiAlN increased with the Ti-content ratio, and its hardness tended to weakly increase with Al-content ratio. The maximum hardness was 36 GPa. Ti-rich film has internal compression stress and Al-rich film has internal tensile stress. (C) 2007 Elsevier B.V. All rights reserved.