The Portable Stack Gas Analyzer, PSGA, device is applicable to measuring the concentration of stack outlet gases including Oxygen (O2), Carbon Monoxide (CO), Nitrogen Dioxide (NO2), Nitrogen Monoxide (NO), Carbon Dioxide (CO2), Sulfur Dioxide (SO2), Ammonia (NH3), Hydrogen Sulfide (H2S) and unburned Hydrocarbons (HC). This device is used to measure the temperature of gas flow up to 600 degrees Celsius and monitor the emitted pollutant gases from the stacks of the factories, houses and so on. In addition to displaying measured data on the LCD and saving them in the internal memory, the PSGA prints all data on the paper by its on-mounted printer