Hypsizygus marmoreus, belongs to Tricholomataceae of Agaricales, is widely cultured as the Beech mushroom in Japan. “Haemi” is the first variety developed by intra-specific crossing in Korea. It was improved with hybridization between monokaryotic strain derived from MKACC51987-8 and MKACC51988- 12. The optimum temperature of mycelial growth and fruiting body development were 23-25℃ and 11~17℃, respectively. The color of fruitingbody was grayish brown and cap type was umbrella. It suggest that 'Haemi' is new commercial variety for consumer who concern over healthy and tasty food