The influence on the head positioning accuracy by aerodynamic excitation in the hard disk drives is growing by high-speed disk rotation and high-density recording in recent years. Therefore, designing the drive in consideration of the influence of aerodynamic excitation to the disk and the arm becomes very important. Especially, the shape design of the shroud that is path of high-speed airflow between disks, and of the arm that supports the head suspension is important. There is a method of experimentally measuring the vibration of the disk and the arm to evaluate the influence of aerodynamic excitation. But a more desirable design becomes possible by establishing the simulation method by the numerical analysis. Up to now, the implement based on the finite element method and the finite difference method has been reported to the airflow analysis for the internal shape in actual HDDs, and the mechanism of aerodynamic excitation is being clarified gradually[1][2]. However, it is necessary to advance in addition to evaluate the influence of aerodynamic excitation more strictly, and to do the structural vibration analysis of arms and disks based on the excitation force that can be calculated by airflow analysis. Then, we developed a very easy-to-use system to calculate airflows in HDD and to follow up with evaluating vibration characteristics of internal structural bodies in HDD. Here, airflow calculation is based on direct numerical simulation not using turbulent models, therefore, more actual fluidic phenomenon can be reproduced.