Writing device drivers is one of the most difficult tasks to develop or port operating systems (OSs). A device driver need to be described according to the target device and OS. And, in the description, programmers must know information about hardware such as specifications of de-vices and carefully describe complex parts such as timing control. This paper proposes a support system for device driver generation. The inputs for the system are device driver specification which shows operations of the device, OS dependent specification which shows dependent parts on the OS, and device dependent specification which shows dependent parts on the device. As an example, network devices is adopted. The inputs to generate device drivers by the proposed system are described. keywords: operating systems, device drivers, network, ethernet, automatic generation.