The shell of Lagochilus concavospirum is small (diameter given by Mollendorff was 4 mm in height, and the 4 mm in diameter). The shell is turbinate, umbilicate, and solid, with transverse striae and low spiral lirae. There are about eight lirae on the body whorl. The spire is elevated, and has concaye sides, with very impressed sutures. The apex is obtuse. There are 5.5 convex whorls. The aperture is nearly circular. The peristome is complete or nearly so, moderately expanded, its upper (posterior) part adnate to the adjacent body whorl.