This study reviewed the status and characteristics of features and artifacts associated with casting ironware from the Proto-Three Kingdoms to Unified Silla, and examined methods of casting ironware on the Korean Peninsula in ancient times based on this evidence. Archaeological sites from the period of the Proto- Three Kingdoms were overwhelmingly centered in the Yeongnam region (the southeastern region of Korea). Cast hoes were produced mainly in the period of the Proto-Three Kingdoms and Three Kingdoms, and cast iron cauldrons in the period of Unified Shilla. A circular or oval melting furnace was installed at the center of one side of a pit created in an oval or square (rectangular) shape. Such furnaces seem to have had a cylindrical shape, with inner diameter and height measuring approximately 30~60cm and 50~100cm, respectively; the cylindrical structure became narrower towards the top. Kilns for baking molds built in ancient times have yet to be investigated, but those that were discovered at Nopodong (Busan) and in Dungi-ri (Ulsan), which were reported as kilns for baking molds of the Joseon Dynasty, did not feature structures that resembled kilns for baking molds as described in a number of historical sources. In addition, molds appear to have been fired in pottery kilns, such as those of Hwangseong-dong (Gyeongju) and Daejeokgol (Jangsu), or in kilns with structures similar to them. The functions and use methods of artifacts unearthed from sites for casting ironware were also examined, including blast pipes, molds, earthenware items of unidentified use, and disc-shaped earthenware products. By comprehensively examining the characteristics of such features and artifacts, the structure of melting furnaces used in ancient times was restored and a plan drawing was suggested in this study. Additionally, the procedure of producing cast ironware in ancient Korea was restored based on the above archeological materials, as well as by referencing the process of casting ironware in areas near Dalcheon Mine, in Ulsan, from the late Joseon Dynasty to modern times, and the production of cast iron cauldrons using the bullmi (“bellow” in the Jeju dialect) craft in Jeju Island. This process was divided into seven stages as follows. In the first stage, raw materials, fuel and furnaces were prepared in advance; in the second and third stages, molds were formed and such molds were produced in kilns, respectively. In the fourth stage, a melting furnace was constructed; in the fifth stage, liquid metal was produced by inserting and melting materials such as pig iron ingots, iron ingots and scrap iron into the melting furnace. In the sixth stage, liquid metal was inserted into the molds; in the last stage, products were separated from the molds and were cut and ground. In this study, this process was suggested using tables and figures; they show that producing cast ironware in ancient times was a time-consuming and labor-intensive process that required very precise techniques, and that the structure of producing and distributing cast ironware began to be undertaken in a systematic manner in Korea from when cast hoes were produced in the period of the Proto-Three Kingdoms.