A microstructural examination on willow leaf shaped iron arrowheads which have close relation with mass production among the various arrowheads excavated from Dangposeong fortress and Soguensanseong fortress was carried out to study the types of the production technology. In addition, previous studies were used to reveal various technologies applied for the production of the arrowheads. The analysis result of 10 willow leaf shaped iron arrowheads from Dangposeong fortress and Soguensanseong fortress suggests that the production process can be classified to three types, ① pure iron-form processing, ② pure ironform processing-carburizing, ③ steel-form processing. However, a ‘welding-form processing and castdecarburizing’ process can be added apart from the three types after considering all the previous studies. It is notable that a number of willow leaf shaped iron arrowheads were fortified using carburizing after form processing for the purpose of functional development. When it comes to considering the purpose of use and characteristics of materials, exclusion of quenching is believed to simplify the manufacturing process for mass production. Hence, existence of nonmetallic inclusions which have similar characteristics with slag in terms of formation of glass phase and w stite suggests that they were made using a solid reduction method.