A new commercial cultivar ‘GARES-HM-17-1’ of Hypsizigus marmoreus was developed by the method of mono-mono crossing between monokaryotic strains derived from Hae-Sal 3Ho. The parental strains are characterized by the property of high quality and a short period of time in cultivation. The optimum temperature of mycelial growth was 25°C and that of fruiting body development was 15~16°C. The period of harvesting including primordia formation was 23.0 days shorter than that of control strain Mangadak No. 2. The color of pileus and stipe surface was neutral-white, respectively. The yield was 82.0±5.8g/850cc plastic bottle. Analysis of the genetic characteristics of the new commercial cultivar ‘GARES-HM-17-1’ showed a different profile as that of the control strain, Mangadak No.2, when RAPD (Random Amplified Polymorphic DNA) primer was used. This new cultivar ‘GARES-HM-17-1’ of H. marmoreus is characterized by the improved quality and a short period of time in cultivation after scratching. It would be of much help to expand the cultivation area of H. marmoreus.