Pb films and self-assembled nanowires on Si(3 3 5) grown at temperature equal to 265 K are investigated by optical reflectance method and scanning tunneling microscopy. In the optical studies s-polarized light with the photon energy from 0.35 to 2.0 eV was used. The measurements were performed during the Pb deposition, for two orientations of the sample: with the light electric field along, and perpendicularly to the Pb nanowires. Two thickness ranges were distinguished: first, for the coverages less than 2 ML, and second, for the larger coverages. The large anisotropy in the optical reflectance was observed in the second range of the thicknesses. The anisotropy was caused by the presence of self-assembled, parallelly aligned metallic nanowires. For the two orthogonal orientations of the sample the reflectance ratio as high as 3.8 was observed.