A semiconductor device design support apparatus for generating a substrate netlist so as to be able to perform substrate noise analysis with high accuracy in a short time. The semiconductor device design support apparatus comprises a unit that divides a semiconductor device layout into a plurality of segments and generates a macro-model of the segments by using a current waveform of an instance included in the divided segments; a unit that replaces a pattern (termed as “substrate interface”) that is designed to be an interface with a substrate with respect to the segments, by a prescribed substrate interface diagram; and a unit that generates a substrate netlist, based on the substrate interface diagram of the plurality of segments.