The present invention relates to an HAPLN1 protein of an aged individual. The HAPLN1 protein has reduced expression during aging and has an excellent effect of alleviating and reversing skin aging including wrinkles when administered. Therefore, by using the difference in the expression, provided are: a biomarker composition for measuring skin aging, capable of diagnosing skin aging； a kit； and a method for screening for skin aging-alleviating agents, comprising a step of detecting the expression level of an HAPLN1 protein or an HAPLN1 gene. In addition, provided are a skin aging preventing or alleviating pharmaceutical composition, cosmetic composition, or health functional food, and a wrinkle alleviating cosmetic composition or health functional food, all of which contain any one or more selected from the group consisting of an HAPLN1 protein, a gene coding for the same, and an effective agent for promoting the expression of the HAPLN1 protein or gene or activating the functions thereof.
