The present invention relates to a novel biarylamide derivative and a pharmaceutical composition or a cosmetic composition comprising the same as an active ingredient. More particularly, the present invention relates to a novel biarylamide derivative, a pharmaceutical composition or a cosmetic composition for preventing or treating a pigmentation disorder caused by an abnormal excess of melanin or a disease caused by melanocyte hyperplasia comprising the same as an active ingredient. The biarylamide derivative of the present invention inhibits melanin production and thus inhibits melanocyte hyperplasia. Therefore, a cosmetic composition comprising the biarylamide is excellent in a whitening effect, and a pharmaceutical composition comprising the biarylamide is effective in the prevention or treatment of pigmentation disorders of skin such as lentigo, melasma, freckle, etc. and malignant melanoma.