Abstract: A composite fiber sponge containing sulforaphane is produced by the step of subjecting a composite liquid to a molding treatment and a crosslinking treatment. The composite liquid contains a composite fiber including an extract of a Brassicaceae plant, a polysaccharide, and a carboxymethyl cellulose fiber. The extract of the Brassicaceae plant contains the sulforaphane. A composite fiber material containing sulforaphane is also disclosed.