Waste gas collecting device

The utility model discloses a waste gas collecting device, which is suitable for equipment capable of generating waste gas during working, and comprises a gas collecting hood used for covering the equipment and a detection device used for acquiring the working state of the equipment, the gas collecting hood is communicated with an exhaust pipeline, the gas collecting hood is provided with a hood body which completely covers the equipment, and the detection device is used for detecting the working state of the equipment. An exhaust valve is arranged on the hood body and controls the exhaust state of the gas collecting hood according to the opening and closing state of the detection device. The gas-collecting hood valve can be automatically started and stopped along with opening and closing of equipment, no waste gas is generated when the equipment is closed, the travel switch is switched off at the moment, the automatic valve is in a closed state, and the gas-collecting hood does not suck gas. When the equipme