A composite material that includes: particles of a two-dimensional material having one or plural layers; and an anionic resin material. The one or plural layers includes a layer body represented by: MmXn, wherein M is at least one metal of Group 3, 4, 5, 6, or 7, X is a carbon atom, a nitrogen atom, or a combination thereof, n is 1 to 4, and m is more than n but not more than 5, and a modifier or terminal T exists on a surface of the layer body, wherein T is at least one of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom. A ratio of the particles of the two-dimensional material to a total of the particles of the two-dimensional material and a solid content of the resin material in the composite material is 50% to 99.9% by mass.