A vehicle body vibration estimating device for estimating a vehicle body vibration as a sprung mass of a vehicle where wheels are suspended via a suspension device. The vehicle body vibration estimating device includes a wheel speed physical quantity detecting section and a vibration estimating section. The wheel speed physical quantity detecting section detects a wheel speed physical quantity related to wheel speed, which is a circumferential velocity of a wheel. The vibration estimating section estimates the vehicle body vibration from a correlation relationship between displacements in a back-and-forth direction and displacements in an up-and-down direction of the wheels with respect to the vehicle body, and the wheel speed physical quantity detected by the wheel speed physical quantity detecting section.