To develop a novel administration method of a fucoidan-containing hair-growing agent and to provide a means for exerting excellent effects of a fucoidan. A hair-growing agent of the present invention is characterized in that it is composed of a combination of a fucoidan-containing microneedle and a fucoidan-containing liniment. Abase of the fucoidan-containing microneedle is preferably a biosoluble polymer. A hair-growing method of the present invention is characterized in that the fucoidan-containing microneedle and the fucoidan-containing liniment are concomitantly used.