A new quartz crystal microbalance-based method has been developed for high-sensitivity detection of trichloroethylene. The method uses oxidizing agents such as lead dioxide and sulfuric acid, by which trichloroethylene is converted into hydrogen chloride, which in turn reacts directly with a copper electrode placed on the quartz crystal surface. The new method enables the measurement of very low concentrations of trichloroethylene, and has a detection limit comparable to the Japanese Environmental Standard (0.2 mg(.)m(-3)).