Button mushroom is one of the popular agricultural products and it is cultivated in 70 countries. It has been cultivated more than 50 years in Korea because it is applied many Korean dishes as nutritional foods. The screening criterion for qualities of button mushroom is very strict and difficult for passing evaluation in Korea; therefore, the mushroom growers are burdened with difficulty in production and consumption in price as well. In this study, the contents of crude fat, fiber, ash, and protein were analyzed in three different qualities of button mushroom as normal, immature, and developed button mushrooms. The contents of crude fat, fiber, ash, and protein were 0.21% 8.68% 0.79% and 2.22% normal product, 0.23% 8.95% 0.86% and 2.41% in immature product, and 0.22% 7.79% 0.82% and 2.22% in developed product, respectively. There was no significant difference in basic nutritional values among the products. Therefore, it is expected that will be loosened the screen criterion of button mushroom, and the producers of button mushroom will be more economically benefits for production as well as the mushroom consumers are more economically consumption for button mushroom by reasonable price.