Etching method for resin molded body and etching processing system for resin molded body

The processing system (1) is provided with an etching tank (2) and a circulation pipe (7) which flows out from the bottom of the etching tank (2) and flows back to the etching tank (2) again. A liquid delivery pump (8), a heat exchanger (9), a sulfuric acid concentration meter (10) and an oxidant concentration meter (11) are arranged in the circulation piping (7). The sulfuric acid concentration meter (10) and the oxidant concentration meter (11) can transmit the measurement results to the calculation/control device (12). In addition, hydrogen peroxide water, sulfuric acid, and pure water can be supplemented to the etching bath (2) by using a hydrogen peroxide water supply line (13), a sulfuric acid supply line (14), and a pure water supply line (15), and the supply amounts of desired amounts of hydrogen peroxide water, sulfuric acid, and pure water can be adjusted by a calculation/control device (12). With such a treatment system, it is possible to etch a resin molded article by maintaining both the sulfuric