Driving support device, method, and storage medium

A driving support device comprises a target determination unit (20) adapted to determine a target position (Z 2e ) ahead of a vehicle and a target vehicle speed at the target position, a target charging electric power setting unit (20) adapted to divide a section between a deceleration start position (O) to start deceleration of the vehicle and the target position into a plurality of sections, and set target charging electric power to different values for respective sections forming the plurality of sections, the target charging electric power charging a battery (45) to generate a regeneration brake that reduces a vehicle speed to the target vehicle speed between the deceleration start position and the target position, and a deceleration control unit (20) adapted to control an electric generator (44) installed in the vehicle to charge the battery with the target charging electric power and to generate the regeneration brake in the respective sections forming the plurality of sections.