Abstract: Disclosed is a control apparatus for correcting the measurement of flow rates for use with a turbine-type flow meter in which the rotation of a turbine rotating in response to the flow velocity of fluid to be measured is detected to produce pulses which are, in turn, integrated to measure the flow rate of the fluid. The apparatus operates to obtain a value representing the rate of reduction in the flow rate from the pulse cycle in order to detect a first time at which the reduction rate increases above a first predetermined value and a second time at which the reduction rate decreases below a second predetermined value, produce a correction value on the basis of the pulse cycle at the second time and the time lag between the first and second times, and integrate pulses other than those generated in the period of time between the first and second times, adding the correction value from the correction value producing means to the integrated value.