Vehicle deceleration force control device and control method thereof

A vehicle deceleration force control device of the invention reduces deceleration force (assist braking force) during implementation of engine brake assist control over a predetermined time (t2-t0) when a vehicle state is changed to an acceleration state by operation of an accelerator. A change amount of the deceleration force over time during reduction is limited to a predetermined value or less. This predetermined value is set to a larger value the steeper the road gradient during hill descent and is set to a smaller value the steeper the road gradient during hill climbing. The vehicle deceleration force control device enables smooth acceleration when shifting from deceleration to acceleration.