The welding of gray cast iron is difficult because it contains a large amount of carbon, which causes the welded part to become brittle. Therefore, several researches have been conducted on welding of gray cast iron. However, none of these studies compared the performance of the joints made using different welding methods and materials. In our study, four kinds of welding methods, namely gas welding, metal-arc welding with covered electrode, semi-automatic arc welding, and TIG welding were applied to the butt joint of a gray cast iron (FC 200). Moreover, eight kinds of specimens were produced by combining the welding materials. Subsequently, the hardness, tensile strength, impact value, workability, and efficiency were quantitatively compared and examined. Based on the results, we arrived at the following conclusions. (1) The gas welding method is not suitable. (2) In metal-arc welding with covered electrode, the tensile strength and impact value of the joint made using the Ni-type welding rod ECNi-CI are high; however, the workability is low. (3) The recommended welding methods are metal-arc welding with covered electrode (E4316), semi-automatic welding (YGW 12), and TIG welding (for repair overlaying).