  We report measurements of the London penetration depth $\Delta\lambda(T)$ and
the electronic specific heat $C_e(T)$ on high-quality single crystals of the
filled-skutterudite superconductor PrPt$_4$Ge$_{12}$ ($T_c\simeq$8K). Both
quantities show a weak temperature dependence at $T\ll T_c$, following
$\Delta\lambda\sim T^n$ ($n\simeq 3.2$) and $C_e/T\sim T^{2.8}$. Such
temperature dependences deviate from both conventional s-wave type and nodal
superconductivity. A detailed analysis indicates that the superfluid density
$\rho_s(T)$, derived from the penetration depth, as well as the electronic
specific heat can be consistently described in terms of a two-gap model,
providing strong evidence of multiband superconductivity for PrPt$_4$Ge$_{12}$.
