FLOWMETER

PURPOSE: To precisely measure a flow rate even in such a case that the distribution of flow speed in a cross-section of a fluid passage is not uniform, and the longitudinal stream lines in the fluid passage varies. CONSTITUTION: Flow speed sensors 121 to 123 , 131 to 133 are arranged at several positions including at least two positions which are different from each other in both longitudinal direction and direction orthogonal to the longitudinal direction. When gas (a) flows through a duct part 11, the flow speed sensors 121 to 123 , 131 to 133 detect flow speeds of the gas at detecting positions 141 to 143 , 151 to 153 . An averaged value of flow speeds is computed from detection signals from the sensors, and a flow rate is computed from the averaged value.