Steiraxis aulaca is a species of sea snail, a marine gastropod mollusk in the family Cochlespiridae.

(Original description) The large, solid shell is white and has a fusiform shape.

The periphery is formed by a sort of rib, on which stand two to four similar keels, but smaller than the others and more crowded.

The outer lip is very flexuous, with a broad, rather shallow anal sulcus behind, and is arched forward in front of the peripheral rib.

The columella is thin, attenuated, and obliquely truncate in front, concave, twisted, exhibiting a pervious axis.