This study aims to examine an effect of multiple dose of collagen and vinegar on the improvement of woman's neck skin. Skin roughness, skin color, melanin and erythema level were measured to comprehend the change of neck skin, so the multiple dose effects of collagen and vinegar were compared and analyzed. In the analysis of neck skin roughness & skin color average variation by increase %, the collagen+vinegar group showed variation of skin roughness with 19.7% (p=0.989), skin color with 4.6% (p=0.672) more than collagen group and vinegar group so it showed the effects of neck skin roughness and skin color changes. In the analysis of the variation of neck melanin levels, though it was not significant but the collagen+vinegar group showed 1.3fold more decreased (p=0.950) in the central neck point part than variation of decreased melanin levels of collagen group (p=0.950). In the analysis of the variation of neck erythema levels, the collagen+vinegar group showed 1.5fold more decreased (p=0.968) in the central neck point part than variation of decreased melanin levels of collagen group.