To provide a circuit board and a multilayer circuit board, which are excellent in heat resistance and adhesion, have a low dielectric constant and a low dielectric loss tangent, and are equipped with an adhesion layer capable of reducing transmission loss even in high frequency transmission.SOLUTION: A circuit board includes an insulating base material layer including a polyimide layer, a conductor circuit layer formed on at least one surface of the insulating base material layer, and an adhesive layer covering the conductor circuit layer. The insulating base material layer has an Evalue of less than 0.009, the Evalue being calculated based on E=vexTandelta...(a) [erepresents a dielectric constant at 10 GHz measured by a split post dialectic resonator (SPDR), and Tandeltarepresents a dielectric loss tangent at 10 GHz]. The adhesive layer contains 50 parts by mole or more of a diamine residue derived from dimer acid type diamine with respect to...
