A new oak mushroom cultivar ‘K815’ was bred from monokaryotic strains of ‘Jadam-2’ and ‘LE191732-118’. The optimal temperature for mycelial growth of ‘K815’ was 25oC, and the temperature for primordia formation and fruiting body development was 15~20oC. The fruiting body morphology is hemispherical and the fruiting form is sporadic. Total cultivation period of the new cultivar, from inoculation to its first harvest, was 133 days, which was 3 days longer than control cultivar ‘Jadam’ (129 days), with 32 days for spawn running, 89 days for browning, 4 days for primordia formation, and 8 days for fruiting body development. In the fruiting body, the thickness and diameter of pileus of the new cultivar were 32.2 mm and 58.3mm, respectively, and the length of stipe was 35.6 mm. Compared to the control cultivar ('Jadam', 'L808'), the pileus of the new cultivar was thicker and smaller and the length of stipe was shorter. The total number of fruiting bodies of ‘K815’ was 58.9, which was higher than the control varieties and total yield of 2 crop cycle of ‘K815’ was 580 g (per 3 kg substrate), which was similar to the control variety.