PURPOSE: To properly control the damping force of a suspension by detecting the status of motion of a body to correct a heave speed.

CONSTITUTION: The outputs from vehicle speed sensors 24a, 24b, 26a, and 26b are integrated by integrating means 36a to 36d to calculate a speed. The speed is input into pitch speed calculation means 40 roll speed calculation means 42 and heave speed calculation means 44. A lateral speed estimation means 46 reads the outputs from angular stroke sensors 28a, 28b, 30a, and 30b to obtain a lateral speed. A heave speed correction means 52 corrects a heave speed using the lateral speed. The corrected heave speed is input into a damping force/output means 54 together with a pitch speed and a roll speed to obtain a damping force required for each of dampers 16a, 16b, 18a, and 18b. Because the heave speed is corrected by detecting the status of motion of the body, the damping force of a suspension can be controlled properly.