Arbutin is a glycosylated hydroquinone found at high concentration in certain plants capable of surviving extreme and sustained dehydration. It has been reported to have an inhibitory effect of melanogenesis and to be hydrolyzed easily to yield glucose and hydroquinone by ${eta}-glucosidase.$ While hydroquinone also has an anti-melanogenic effect, however, is carefully used as a topical whitening agent because of side effects. The present study was undertaken to examine the inhibitory effect of an whitening agent containing arbutin and ${eta}-glucosidase$ on UV radiation induced pigmentation in human skin. Experimental subjects were UVB-irradiated on the back. UVB-irradiated areas were assigned to three groups: arbutin and ${eta}-glucosidase$ treated group, vehicle control, and no-application control. Arbutin and ${eta}-glucosidase$ treatment inhibited pigmentation by 50.17 percent, compared with the controls (N : 10: P<0.05). These results suggest that the whitening agent containing arbutin and ${eta}-glucosidase$may be used as an agent to inhibit melanin formation induced by UV radiation.