[en] We have systematically investigated the current-voltage (I-V), absorbance and optical band gap of TiO_2 thin film prepared through varying the molarity of the TiO_2 precursor by sol-gel spin coating technique. In addition to the electrical and optical characteristics, the surface morphology was examined by using Atomic Force Microscope (AFM). From the image of the AFM, we were able to observe the uniformity of the TiO_2 thin film. From the experimental results, we found that the uniformity of the TiO_2 thin film is optimized at 0.2M sample. It is also found that, as the molarity increased, there is tendency of the resistivity to decrease. Not only that, the absorbance measurement and optical band gap also gave its best value for 0.2M sample. Therefore, in this work it is concluded that 0.20M of TiO_2 gave the best characteristics for all measurements. (paper)