An antiviral agent is provided which has an excellent effect on a non-enveloped virus and which is highly safe to the human body, and an antiviral composition which comprises the antiviral agent and which is useful for disinfection of the virus or prevention of infection of the virus. The antiviral agent comprises as an active ingredient an extract from a plant of the genus Diospyros containing tannin, a catechin, wattle tannin, pentagalloyl glucose, coffee tannin, an alkyl gallate (excluding that in the above-described persimmon extract), pyrogallol, or an organic acid and/or a salt thereof (excluding that in the above-described persimmon extract). The antiviral composition is characterized by comprising at least the antiviral agent and an alcohol, a surfactant, a microbicide, a humectant, or a cosmetic fat and oil, and preferably further comprises citric acid and/or a salt thereof or vitamin C.
