Humidity sensors using $TiO_2$ thin films were fabricated on the multi-electrode device by Sol-Gel method and their wettability, surface potential decays and humidity sensing characteristics were investigated. Contact angle of thin films was $28^{cic};at; 400^{circ}C$ and surface potential decayed rapidly at $400^{circ}C$. The specimen showed best humidity sensing characteristics at $400^{circ}C$. From the results, they were confirmed that humidity sensing characteristics of thin films have connection with contact angle and surface potential decays.