Provided is niacin-peptide which has skin whitening activity. The peptide of the present invention has skin whitening activity by inhibiting melanogenesis, that is, by inhibiting the expression of a gene related to melanogenesis (for example, TRP-1, TRP2, or MIFT). The peptide of the present invention has high stability and skin permeability. Also provided is a cosmetic composition for skin whitening which contains the niacin-peptide.