A semiconductor circuit in which low impedance characteristics required for a decoupling circuit are ensured up to a band of several hundreds of MHz or above in the situation where digital circuits are rushing into GHz age, and a semiconductor circuit exhibiting low impedance characteristics even in a band of several hundreds of MHz or above. A line element comprising a power supply line and a ground line or a ground plane arranged oppositely through a dielectric, characterized in that a dielectric covering the line element is provided.