Hukbaek oyster mushroom were bred and cultivated one after mating spores from Aenutari 1-ho irradiated to X-ray and Byungnutari 1-ho. The major charateristics of the mushroom are showing that pileus is black-brown and stems are pure-white and straight. The optimum temperature for the mycelial growth was around $25{sim}30^{circ}C$ and that for the pinheading and growth of fruitbody was around $14{sim}16^{circ}C$. Around 20 days at $20^{circ}C$ were required for incubation time and the yield was shown high by 142.8g/bottle. When the cultivating temperature is over $17^{circ}C$ the color of pileus becomes gray-brown.