A circuit board including a substrate having first and second dielectric layers of first and second dielectrics, the second dielectric containing 8 mass % or more of a glass net former component. At least one portion of an inner layer electrode has approximately two principal surfaces parallel to principal surfaces of the circuit board and a thickness of not less than 50 micrometers in a normal direction of the principal surfaces. The inner layer electrode and second dielectric layer contact with each other, and a ratio t/T of sum total thickness t of the second dielectric layer in contact with the inner layer electrode in a normal direction of the principal surface to sum total thickness T of the first dielectric layer in a normal direction of the principal surface is 0.1 or more.