PROBLEM TO BE SOLVED: To provide a method for evaluating prevention efficiency for secondary pollution by microorganisms in a nonaqueous skin external product.SOLUTION: An evaluation method of efficiency for secondary pollution prevention of a nonaqueous skin external product comprises the steps of: (1) contacting at least one kind of substrate selected from the group consisting of microorganisms, keratinocyte, protein and peptide, on a surface of the nonaqueous skin external product, with at least one kind of auxiliary substrate selected from the group consisting of amino acid, saccharides, vitamins, metal salt and lipid (2) maintaining the nonaqueous skin external product of the step (1) for a predetermined period under a humidity condition in which microorganisms can be grown and (3) evaluating produced smell or proliferative of microorganisms in the nonaqueous skin external product of the step (2).
