  We report the results of angle dependent resistivity of
NdFeAsO$_{0.82}$F$_{0.18}$ single crystals in the superconducting state. By
doing the scaling of resistivity within the frame of the anisotropic
Ginzburg-Landau theory, it is found that the angle dependent resistivity
measured under different magnetic fields at a certain temperature can be
collapsed onto one curve. As a scaling parameter, the anisotropy $\Gamma$ can
be determined for different temperatures. It is found that $\Gamma(T)$
increases slowly with decreasing temperature, varying from $\Gamma \simeq$ 5.48
at T=50 K to $\Gamma \simeq$ 6.24 at T=44 K. This temperature dependence can be
understood within the picture of multi-band superconductivity.
