Organic materials or polymers, which are widely used in electronic devices, are easily damaged by energetic ion or electron bombardment. Therefore, it is difficult to use conventional ion or electron beam processes for etching organic materials. In this study, a gas cluster beam possessing kinetic energy of the order of several hundred eV was used as a novel means to realize high-rate, low-damage etching. Polyethylene (PE) and polyvinyl chloride (PVC) were used as the target organic materials. Using a SF6 cluster beam, the etching depth suddenly increased when the nozzle gas pressure exceeded 0.6 MPa, as in the case of cluster beam formation. When the SF6 gas pressure in the nozzle was 1.2 MPa, the etching rates of PVC and PE were 2.88 μm/s and 1.62 μm/s, respectively. The dependence of the etching effect on cluster size was studied by varying the gas temperature. The etching depth of PVC increased with increasing average cluster size and intensity of the beam. The flow rate of the gas was constant; hence, etching of the organic materials did not occur because of the individual impact of the molecular beam. In fact, it occurred because of the neutral cluster, which had a large total kinetic energy. The energy per molecule of the gas cluster beam is of the order of several tens of meV; hence, high-rate, low-damage etching of organic materials can be potentially achieved.