In order to provide a flow rate measurement device that can measure a flow rate of a sample fluid passing a tube body with high accuracy even though temperature irregularity of the sample fluid generates along a radial direction of the tube body, the flow rate measurement device comprise a temperature measurement device that measures a mean temperature of a sample fluid discharged from an internal combustion engine or temperature distribution of the sample fluid along a radial direction of the tube body, and a flow rate of the sample fluid is measured based on the mean temperature or the temperature distribution measured by the temperature measurement device.