PROBLEM TO BE SOLVED: To realize a circuit board and an electronic device which have high heat radiation effect.SOLUTION: A heat diffusion layer 12 is provided in a circuit board 10A, and a porous heat radiation layer 13 is provided on a surface of the circuit board 10A. The heat diffusion layer 12 and the heat radiation layer 13 are connected by using a via 11b and a wiring layer 11a. Heat transmitted to the heat diffusion layer 12 is transmitted to the heat radiation layer 13 through the via 11b and the wiring layer 11a to be radiated. Providing the porous heat radiation layer 13 realizes the circuit board 10A having a large heat radiation area and high heat radiation effect. An electronic device having high heat radiation effect is realized by using the circuit board 10A.
