Many enterprises are performing the production planning computerization for survival in unlimited competing period. But it is very difficult to directly apply many production planning softwares to the domain-specific areas of many small enterprises because one enterprise is different from the others with respect to product type, production process, and order fulfillment method. Practically most small enterprises depend on experienced production managers in production planning, so then many problems such as overtime work and cost have been appeared. The purpose of this study is to develop production planning module for order-made production system in order to reduce overtime works and surplus costs. We developed production planning module with RDBMS, which is fit for small manufacturing company. Developing this software, we use Visual Basic 5.0 to provide GUI environment for the production planning module and Microsoft Access 97 is used to construct Database. This production planning module is applied to enhancement of productivity in M manufacturing company located in Asan.