  We measured the electrical resistivity and the $^{121}$Sb nuclear quadrupole
resonance (NQR) spectra of La$_3$TiSb$_5$, which is a nonmagnetic reference
system for a locally noncentrosymmetric antiferromagnet Ce$_3$TiSb$_5$, in
order to determine its physical properties. The resistivity exhibited a hump
anomaly at 120 K, suggesting a phase transition. The NQR spectra split below
110 K, whereas the nuclear spin-lattice relaxation exhibited no anomalies.
These results can be explained by the incommensurate charge-density-wave (CDW)
transition. This finding suggests the importance of quasi-one-dimensional
characteristics and CDW instability in these systems.
