The reinforcing cord of the present invention includes at least one strand. The strand includes a bundle of filaments that are bundled and twisted together in one direction, and a coating layer that is formed on at least the surface of the bundle. The bundle consists essentially of carbon fiber filaments. The coating layer is a coating layer that is formed from an aqueous treatment agent containing a rubber latex and a crosslinking agent as essential components and a filler as an optional component. In the aqueous treatment agent, the total of the mass of the crosslinking agent and the mass of the filler is in a range of 1 to 50% of the mass of rubber in the rubber latex.