Climate change threatens global food security and farm management by affecting the quantity and quality of food. Our purpose is to accurately predict the effect of climate change on rice production in Japan. To estimate the rice quantity and quality under the future climate conditions, we simulated rice growth and quality models by three different scenarios of greenhouse gas (GHG) emission. For assessing the economic impact of climate change, we exchanged the results of rice yield and quality to the price. We focus on Kosihikari, the most popular cultivar among consumers and widely produced in Japanese rice farming, although being vulnerable to heat stress. The estimated results provide two insights. First, an increase in the quantity of rice yield due to climate change has a stronger economic impact than the decrease in quality even under the future climate conditions scenario with the lowest GHG-emission. Second, the impact between eastern and western Japan is different. In eastern Japan, the rice yield would increase while in western Japan, quality would deteriorate. This means the Japanese will be faced with an oversupply of rice, and suggests that rice farmers in western Japan will be obliged to adopt new strategies to improve revenue. Acknowledgement :