An improved structure for mounting minor and major filaments of a three-way incandescent lamp is disclosed. The improved mounting structure orients the major filament in either an axial or transverse manner and the minor filament in a transverse manner. The transverse mounting of the major and minor filaments is established by the selection of the respective parameters of the inner lead wires connected to the minor and major filaments so as to improve the ability of each transverse mounted filament to withstand mechanical shock.