In order to satisfy various desires of consumers, a company should produce a variety of products and the production lot size should be as small as possible inevitably. Then, it requires frequent setup works for the model changes. Since setup works are usually carried out after stopping the operation of the equipment, we must minimize the time required for setup works. Major companies are continuously shortening the setup time over the technical guidance from the leading companies, such as Toyota and their own improvement activities up until now. But small and medium-sized(S&M) companies rely on skills and experience of individual engineers due to lack of the personnel and budget. In this paper, we propose systematic guidelines for writing the setup operation manual to support S&M companies. Major functions of the guidelines are drawing process charts specialized in the setup operation, separating the external and internal setup operations, and minimizing internal setup operations. By utilizing the guidelines, it is expected that S&M companies can prepare and apply their own setup operation manual with a minimum of manpower and money. Then, they can manage setup works in a more efficient and reduce the setup time and lower the production cost.