The present disclosure relates to HAPLN1 protein of an aged individual. The HAPLN1 protein exhibits reduced expression with aging, and when administered, its effect in alleviating and reversing skin aging including wrinkles is excellent. Therefore, by exploiting the difference in expression, provided are a biomarker composition for measuring skin aging, capable of diagnosing skin aging； a kit； and a method of screening for skin aging alleviating agents, comprising detecting the expression level of HAPLN1 protein or HAPLN1 gene. In addition, provided are a pharmaceutical composition, cosmetic composition, or health functional food for preventing or alleviating skin aging, and a cosmetic composition or health functional food for alleviating wrinkles, each containing any one or more selected from the group consisting of HAPLN1 protein, a gene encoding the same, and an effective agent for promoting the expression or activating the functions of HAPLN1 protein or gene.
