Carbon fiber for an aqueous process and cut carbon fiber for an aqueous process.

A carbon fiber dispersible in water, which is formed by convergence of a plurality of individual fibers, wherein the oxygen concentration at the surface (O / C) of each of the single fibers is 0.03 or greater, and less than 0.12, as measured by photoelectron spectroscopy X-ray (ESCA) and a sizing agent containing a surfactant as a main component in an amount which is 70% by weight or more, it has adhered the individual fibers, such carbon fiber forming a first contact angle with water of 75 ° or less, as measured by the Wilhelmy method.