PROBLEM TO BE SOLVED: To reduce a jolt of a vehicle. SOLUTION: A predecessor vehicle jolt detection part 11 and an own vehicle jolt detection part 12 create jolt data of a predecessor vehicle jolt and jolt data of an own vehicle jolt from data of image in front of the vehicle taken by a camera part 2 respectively. The created two jolt data sets are entered into a roll estimation part 13. The roll estimation part 13 estimates a jolt to be given to the own vehicle from the entered two jolt data sets. A reverse jolt generation part 14 creates reverse jolt data to reduce the jolt to be given to the own vehicle based on the data of the jolt estimated by the jolt estimation part 13. A reverse roll actuator 4 is controlled according to the reverse jolt data to reduce the jolt to be given to the own vehicle.