With the exhaust gas measuring device and the exhaust gas measuring method, the workload of the internal combustion engine is calculated based on a discharged amount of a component related to a carbon compound such as CO, CO2 and THC in the exhaust gas discharged from the internal combustion engine. As a result, the workload of the internal combustion engine can be calculated easily without using torque data of the ECU and the mass of each component in the exhaust gas discharged from the internal combustion engine per unit workload can be calculated.