The present invention relates to: a gold-nanodiamond composite maintaining color stability for a long time even in a heated or acidic and neutral condition by allowing gold to be coupled to the surface of a nanodiamond； and a cosmetic comprising the same. The present invention can maintain the dispersion characteristics of nanodiamonds and the intrinsic characteristics (intrinsic color and antioxidant ability) of gold nanoparticles by forming gold in an island form on the surface of a nanodiamond, which is a three-dimensional scaffold. In addition, the composite of the present invention uses a nanodiamond as a three-dimensional scaffold so as to be nontoxic, and prevents, by diamond dispersion characteristics, aggregation between gold nanoparticles so as to facilitate redispersion and can maintain the intrinsic color of gold nanoparticles without discoloration regardless of a heating or pH change condition to be applied during the preparation of cosmetics. Additionally, the present invention can uniformly form gold nanoparticles (4-20 nm) on the surface of a nanodiamond in a short amount of time, and thus a process is simple, and a composite in which gold nanoparticles having a uniform size is formed on the surface of a nanodiamond can be obtained in a high yield.La présente invention concerne : un composite or-nanodiamant qui conserve sa stabilité de couleur pendant longtemps même dans une condition de chauffage ou acide et neutre par couplage de l'or à la surface du nanodiamant ； et un produit cosmétique le comprenant. La présente invention permet de conserver les caractéristiques de dispersion des nanodiamants et les caractéristiques intrinsèques (couleur intrinsèque et capacité antioxydante) des nanoparticules d'or par formation d'un îlot d'or sur la surface d'un nanodiamant, qui est un échafaudage tridimensionnel. De plus, le composite selon la présente invention utilise un nanodiamant comme un échafaudage tridimensionnel de façon à être non toxique, et empêche
