In industries, particularly the construction field, the number of workers is decreasing because of the falling number of young new hires and the increasing number of existing elderly workers. Therefore, it is important to improve the productivity of each worker at a construction site. At many construction sites, operation and decision-making skills of construction machine operators are required, and work productivity depends on these skills of the operators. However, the number of elderly skilled operators is decreasing, and it is necessary to accurately train young unskilled operators to develop the aforementioned skills in order to improve productivity. Thus, a system that can quantitatively evaluate the operation skills of the operator is required. This study proposes a system that can quantitatively evaluate the operator's skills by using a database-driven technique. The proposed method is applied to the swing operation of a hydraulic excavator. Furthermore, skill evaluation is carried out by multiple operators, and the effectiveness of the proposed method is verified.