The carbon fiber forming raw material is a carbon fiber forming raw material (Z) as a prepreg including sizing agent-coated carbon fibers and a thermosetting resin or a carbon fiber forming raw material (Y) as a forming material that includes sizing agent-coated carbon fibers and has a woven fabric form or a braid form. The sizing agent includes components (A) and (B). The component (A) is an epoxy compound having two or more epoxy groups or two or more types of functional groups. The component (B) is one or more compounds selected from the group consisting of a tertiary amine compound, a tertiary amine salt, a quaternary ammonium salt, a quaternary phosphonium salt, and a phosphine compound. The component (B) is contained in an amount of 0.1 to 25 parts by mass relative to 100 parts by mass of the component (A).