The purpose of this study is basically for the use of simulations to enhance productivity. In this paper, the optimal number of allocation in a small and medium industry which produces eleutherococcus senticosus sap, is performed using simulations. The simulation model was developed under considerations of production layout, process & operation, process time, total work time, work in process (WIP), utilization, failure rate, and operation efficient as inputs, and was validated with careful comparisons between real behaviors and outputs of the production line. Therefore, we can evaluate effects and changes in productivity when some strategies and/or crucial factors are changed. Although too many workers and machines could decrease productivity, the eleutherococcus senticosus sap production line in this paper has been maintained many machines. To solve this problem, we determined the optimal number of workers and machines that could not cause any interrupt in productions using simulations. This simulation model considers diverse input variables which could influence productivity, and it is very useful not only for the production line of Eleutherococcus Senticosus Sap, but also for other production lines with various purposes, especially, in the small and medium industries.