A circuit board has plated through holes which are laid out with a fine pitch and meets requirements relating to characteristics such as strength and thermal expansion coefficient. A method of manufacturing a circuit board includes: a step of forming a core portion by thermal compression bonding prepregs formed by disposing carbon fibers so as to produce openings at positions where plated through holes will pass through and impregnating the carbon fibers with resin; a step of forming through holes that pass inside the openings at positions of the openings in the core portion; and a step of forming a conductive layer on inner surfaces of the through holes to form plated through holes at positions that do not interfere with the carbon fibers and thereby produce a core substrate.