The purpose of this study is to analyze the coal cartels of Japan and Britain by comparing the difference. There are four factual findings: (1) the cartels facilitated the stabilization of coal prices, (2) the coefficient of variation of Britain’s coal price was higher than that of Japan during the cartel periods, (3) the methods of cartels in both countries were similar in productions and sales, and (4) the coordination functions in coal fields were important for the cartels.