A grinding machine includes a grinding machine body and a grinding disc connected to the grinding machine body. The grinding machine body is provided with a pressure cavity at a position facing the grinding disc and a gas intake pipe corresponding to the pressure cavity. A pressure release gap in communication with the pressure cavity is formed between the grinding machine body and the grinding disc. The gas intake pipe induces a high-pressure gas into the pressure cavity, which receives an effect of the high-pressure gas to become a positive-pressure environment. The high-pressure gas is continually released via the pressure release gap to prohibit external dust from entering the pressure cavity. Thus, the grinding machine is capable of preventing dust from accumulating in the pressure cavity as well as effectively preventing moisture from entering the pressure cavity when the grinding machine is applied for wet grinding.
