PURPOSE: To detect abnormality successively during vehicle drive by comparing the vehicle speed obtained based on vehicle driving states other than a vehicle speed with a vehicle speed detected by a vehicle speed sensor.

CONSTITUTION: A vehicle speed detecting device detects the vehicle speed based on the vehicle speed signal from the vehicle sensor coupled with a propeller shaft. A vehicle driving state detecting means, on the other hand, detects vehicle driving states including at least the rotating speed of an internal combustion engine except the vehicle speed. Further, a vehicle speed storage means stores a set vehicle speed which is a specific speed lower than a vehicle speed forecasted according to the driving states detected by the driving state detecting means and a vehicle speed retrieval means retrieves the vehicle speed stored in the vehicle speed storage means based on the detected driving states. Then, a vehicle speed sensor abnormality detecting means compares the retrieved vehicle speed with the vehicle speed detected based on the vehicle speed signal from the vehicle speed sensor to detect the abnormality of the vehicle speed sensor and an abnormality detection signal output means outputs a vehicle speed abnormality detection signal at the time of the vehicle speed sensor abnormality detecting means detects the abnormality.