This research aims to investigate structural changes of household consumption in Japan from 1980s to 2013, shedding light on problems caused by demand-saturation. The author conducts quanti- tative empirical analyses based on publicly accessible economic data provided by the Government of Japan. The results show the following four suggestions: Firstly, the prior results of researches based on U.S. economy whose income gap has been widened with the increase of income level in the top-income class are difficult to apply to the Japanese demand-saturation mainly because even the income level of the highest-income class in Japan has been decreasing since late 1990s. Secondly, the consumption curve of Japanese household might have been shifting downward from 1980s to early 2010s. The shift might cause increases of the average propensity of consumption from late 1990s to early 2010s. Thirdly, increases of the average propensity of consumption from late 1990s to early 2010s are not uniform among income classes. The propensities of lower-income classes increased, but those of higher-income classes stayed at the same level. Fourthly, propensities of consumption of durable goods might have been decreasing in all income classes. In conclusion, the author suggests that all of the income classes, including the top one, might be trapped in problems by demand-saturation in 2000s’ Japan.
