A dry etching system capable of suppressing the effect of reaction products generated in a reaction chamber during an etching process to the edge profile of an etch object such as a semiconductor wafer. This system includes a reaction chamber in which an etching action is performed, a plasma generator for generating plasma in the reaction chamber, a holder for holding an etch object in the reaction chamber, a detector for detecting the quantity of a reaction product contained in the plasma, and a controller for controlling the amount of the reaction products contained in the plasma to be at least one specific value. The etch object is etched by the action of etching species contained in the plasma. The detector detects, for example, the intensity of light emission from the plasma at a specific wavelength. The controller preferably includes a distance adjuster for adjusting the distance between a dielectric plate and an induction coil, thereby controlling the amount of the reaction products contained in the plasma.