It is required to devise a way to reduce the quantity of zinc pyrithione added to hair care products as the anti-dandruff agent in order to lower the stimuli to the ocular mucosa and in order to reduce the influence on the environment of domestic wastewater and a way to accelerate the decomposition thereof in sewage treatment facilities, rivers, lakes, or ponds. Further, zinc pyrithione contained in ship bottom paints as the antifouling agent is eluted from the coating films at a high rate and thus results in poor long-term antifouling effect, so that it is also required to devise a way to lower the solubility thereof in seawater. The problems can be solved at once by an antibiotic composition obtained by making either zinc pyrithione or a zinc pyrithione/zinc oxide composite compound adsorbed to hydrous titanium oxide.