A capacitor-embedded substrate includes a base material having a desired thickness, and a pair of conductors (feedthrough electrodes) each formed in a desired pattern to penetrate through the base material in the thickness direction thereof, and oppositely disposed with an insulating layer interposed therebetween. The pair of electrodes are formed in comb-shaped patterns, and are oppositely disposed in such a manner that respective comb-tooth portions are meshed with each other.