A sensor characteristic correction device is configured to detect a characteristic of a first sensor arranged upstream of a catalyst 6 in an exhaust passage 4 of an internal combustion engine 2, and a characteristic of a second sensor that is an air-fuel sensor 12 arranged downstream of the catalyst 6, to calculate a first air-fuel ratio based on the characteristic of the first sensor, and calculates a second air-fuel ratio based on the characteristic of the second sensor, to detect, when the catalyst 6 is in an inactive state after start-up of the internal combustion engine 2, a difference between the first characteristic and the second characteristic or a difference between the first air-fuel ratio and the second air-fuel ratio, and to correct the responsiveness of the first or the second sensor in accordance with the difference.