This study delineated the structure of the refrigerator line-ups of the four major manufacturers during the past two decades. Refrigerators were classified by the functions and layouts of the compartments, since particular importance was attached to the components in the development of refrigerators. The result revealed that there were 22 combinations of the functions, or 48 types if the difference in layout was considered. The line-ups of the manufacturers were described by 48 types, and analyzed in time series by the quantification theory III. It was confirmed that the manufacturers developed their unique line-ups and deployed them discretely by the periods. Although the line-up changes were continuous within a period, there were two types of changes, continuous and consecutive, when their occurrence extended over plural periods. In terms of time series, the 48 types were classified into three groups; the basic type group, the trendy type group, and the limited period type group. The line-ups were structured by combinations of these types.