A driving support device for a vehicle, comprising: a collision avoidance support system comprising: obstacle detection means for detecting an obstacle existing ahead of an own vehicle; first command value calculation means for calculating, when said own vehicle is likely to have a collision with said detected obstacle, a first steering control command value (Tr1(n)) representing a control amount of a steered wheel for avoiding said collision; and collision avoidance control means for carrying out steering control for said steered wheel in accordance with said first steering control command value; and a lane travel support system comprising: lane detection means for detecting a lane in which said own vehicle is traveling; second command value calculation means for calculating a second steering control command value (Tr2(n)) representing a control amount of said steered wheel for maintaining a travel of said own vehicle along said lane based on a departure amount representing a degree of departure of said own vehicle from said detected lane; and lane travel control means for carrying out steering control for said steered wheel in accordance with said second steering control command value, characterised in that said first command value calculation means has such a first calculation characteristic that an upper limit value of said first steering control command value is set to a first upper limit value (Trmax1), and an increase gradient per unit period until said first steering control command value reaches said first upper limit value is set to a first gradient; said second command value calculation means has such a second calculation characteristic that an upper limit value of said second steering control command value is set to a second upper limit value (Trmax2), and an increase gradient per unit period until said second steering control command value reaches said second upper limit value is set to a second gradient; and said first upper limit value is set to a value less than said second upper limit value (Trmax1<Trmax2), and said first gradient is set to a value more than said second gradient (K1>K2). a collision avoidance support system comprising: obstacle detection means for detecting an obstacle existing ahead of an own vehicle; first command value calculation means for calculating, when said own vehicle is likely to have a collision with said detected obstacle, a first steering control command value (Tr1(n)) representing a control amount of a steered wheel for avoiding said collision; and collision avoidance control means for carrying out steering control for said steered wheel in accordance with said first steering control command value; and obstacle detection means for detecting an obstacle existing ahead of an own vehicle; first command value calculation means for calculating, when said own vehicle is likely to have a collision with said detected obstacle, a first steering control command value (Tr1(n)) representing a control amount of a steered wheel for avoiding said collision; and collision avoidance control means for carrying out steering control for said steered wheel in accordance with said first steering control command value; and a lane travel support system comprising: lane detection means for detecting a lane in which said own vehicle is traveling; second command value calculation means for calculating a second steering control command value (Tr2(n)) representing a control amount of said steered wheel for maintaining a travel of said own vehicle along said lane based on a departure amount representing a degree of departure of said own vehicle from said detected lane; and lane travel control means for carrying out steering control for said steered wheel in accordance with said second steering control command value, characterised in that lane detection means for detecting a lane in which said own vehicle is traveling; second command value calculation means for calculating a second steering control command value (Tr2(n)) representing a control amount of said steered wheel for maintaining a travel of said own vehicle along said lane based on a departure amount representing a degree of departure of said own vehicle from said detected lane; and lane travel control means for carrying out steering control for said steered wheel in accordance with said second steering control command value, characterised in that said first command value calculation means has such a first calculation characteristic that an upper limit value of said first steering control command value is set to a first upper limit value (Trmax1), and an increase gradient per unit period until said first steering control command value reaches said first upper limit value is set to a first gradient; said second command value calculation means has such a second calculation characteristic that an upper limit value of said second steering control command value is set to a second upper limit value (Trmax2), and an increase gradient per unit period until said second steering control command value reaches said second upper limit value is set to a second gradient; and said first upper limit value is set to a value less than said second upper limit value (Trmax1<Trmax2), and said first gradient is set to a value more than said second gradient (K1>K2).