When the plasma mumbrane of the yeast Rhodotorula minuta cells was exposed to near-UV at 0℃, three new compounds were formes photochemically with decrease in ergosterol content. When 0.4%-SDS solution containing ergosterol was illuminated with near-UV, the same three compounds as in the membrane were formed. As a result of instruments analysis, one of three photochemical products was identified as previtamine D2 and another two compounds were characterized chemically that they had the structure of ergosta-4, 7, 22-trein-3-on. In addition, these photochemical products did not affect the growth and carotenogenesis of the yeast Rhodotorulaminuta.