Disclosed in the specification is a skin whitening composition comprising as an effective ingredient a Pseudoalteromonas carrageenovora strain, a lysate thereof, a culture thereof, or an extract from the strain, lysate, or culture. Also, the specification discloses a Pseudoalteromonas carrageenovora SNC 121 strain, deposited with accession number KCCM12049P, which exhibits a skin whitening function.