In order to provide a correction device that enables the accuracy of the linearity between sensor output values and flow rate values in a flow rate sensor, there are provided a sensitivity correction function storage unit that stores a sensitivity correction function in which at least a portion of sensitivity correction values are set to different values in accordance with the sensor output values output from a flow rate sensor in an initial state in which the sensitivity coefficient is set to an initial value, a sensitivity setting unit that sets the sensitivity coefficient based on the initial values and on the sensitivity correction function, and then adjusts the sensitivity of the flow rate sensor, and a coefficient calculation unit that calculates a post-correction flow rate characteristic function based on function correction values that are decided in accordance with the flow rate values output post sensitivity correction.