Thin films of single-wall carbon nanotubes (SWNT) with various thicknesses were fabricated, and their optical and electrical properties were investigated. The SWNTs of various thicknesses were directly coated in the arc-discharge chamber during the synthesis and then thermally and chemically purified. The crystalline quality of the SWNTs was improved by the purification processes as determined by Raman spectroscopy measurements. The resistance of the film is the lowest for the chemically purified SWNTs. The resistance vs. thickness measurements reveal the percolation thickness of the SWNT film to be ~50 nm. Optical absorption coefficient due to Beer-Lambert is estimated to be 7.1 × 10-2 nm-1. The film thickness for 80% transparency is about 32 nm, and the sheet resistance is 242Ω/sq. The authors also confirmed the relation between electrical conductance and optical conductance with very good reliability by measuring the resistance and transparency measurements.