  Intermetallic R$_3$T$_4$X$_{13}$ series consists of cage like structure and
have been in focus due to their unconventional electronic ground states. In
this work, we report the normal and superconducting state properties of a high
quality single crystal of Lu$_3$Os$_4$Ge$_{13}$. Lu$_3$Os$_4$Ge$_{13}$ belongs
to the above mentioned series and crystallizes in a cubic crystal structure
with the space group $\it{Pm\bar{3}n}$. Using electrical transport,
magnetization and heat capacity measurements, we show that
Lu$_3$Os$_4$Ge$_{13}$ is a type-II multi-band superconductor ($T{_c} =3.1$~K)
with unusual superconducting properties. The analysis of the low temperature
heat capacity data suggests that Lu$_3$Os$_4$Ge$_{13}$ is a moderately coupled
multi-band BCS superconductor with two gaps ($2\Delta / {k{_B}T{_c}} = 3.68 \pm
{0.04} ~\& ~0.34 \pm {0.02}$) in the superconducting state. The
dc-magnetization ($M-H$) shows a large reversible region in the superconducting
state similar to the vortex liquid phase observed in high-$T{_c}$
superconductors. The value of the Ginzburg number $G_{i}$ suggests that the
thermal fluctuations, though small as compared to those in high-$T{_c}$
cuprates, may play an important role in the unpinning of the vortices in this
compound. The electronic band structure calculations show that three bands
cross the Fermi level and constitute a complex Fermi surface in
Lu$_3$Os$_4$Ge$_{13}$
