A curving tendency detection device is provided to detecting a curving tendency (curving frequency and amount of curvature) in a vehicle roadway or a vehicle running state (behavior). Basically, the curving tendency detection device has a lateral acceleration differential value calculation section and a curving tendency estimation section. The lateral acceleration differential value calculation section calculates vehicle lateral acceleration differential values of a vehicle lateral acceleration acting on a vehicle as the vehicle lateral acceleration varies over time. The curving tendency estimation section estimates the curving tendency based on the vehicle lateral acceleration differential value calculated by the lateral acceleration differential value calculation section. Thus, the curving can be reliably detected by effectively avoiding a false curving tendency in cases in which the left and right wheels have different effective diameters, or the vehicle is driving straight along a laterally tilted road.