PRELIMINARY BRAKING DEVICE AND PRELIMINARY BRAKING METHOD

A preliminary braking device 10 includes a following vehicle detection unit 12 configured to detect vehicle speed of a following vehicle 300 following a vehicle 100 and an inter-vehicle distance D to the following vehicle 300, a deceleration area detection unit 14 configured to detect a deceleration area 30 in a traveling lane 31 ahead of the vehicle 100, and a braking activation unit 17 configured to, when the inter-vehicle distance D to the following vehicle 300 is smaller than a predetermined value when the vehicle 100 passes through a position before the deceleration area 30 by a predetermined distance, cause a brake system to activate preliminary braking for generating deceleration smaller than or equal to a predetermined value.