A driving assist device comprising an electronic control unit configured to perform a deceleration assist, the deceleration assist being a deceleration assist by which a vehicle is decelerated to a target velocity before the vehicle reaches a target position, the electronic control unit being configured to recognize a situation in front of the vehicle, the electronic control unit being configured to determine whether the target position is able to be decided from a predetermined object, when the electronic control unit recognizes that the predetermined object exists in front of the vehicle, the predetermined object indicating that the vehicle needs to be decelerated, the electronic control unit being configured to perform a first assist as the deceleration assist when the electronic control unit determines that the target position is not able to be decided, the first assist being an assist by which the vehicle is decelerated at a first deceleration, the first deceleration being changed based on a brake operation by a driver, wherein an initial value of the first deceleration is a sum of a deceleration that is demanded by the brake operation at a time point of start of the brake operation and a deceleration that is generated in the vehicle at the time point due to the deceleration assist, and the electronic control unit being configured to perform a second assist as the deceleration assist when the electronic control unit determines that the target position is able to be decided, the second assist being an assist by which the vehicle is decelerated at a second deceleration, the second deceleration being equal to or higher than a predetermined deceleration necessary to decelerate the vehicle to the target velocity before the vehicle reaches the target position decided from the predetermined object. an electronic control unit configured to perform a deceleration assist, the deceleration assist being a deceleration assist by which a vehicle is decelerated to a target velocity before the vehicle reaches a target position, the electronic control unit being configured to recognize a situation in front of the vehicle, the electronic control unit being configured to determine whether the target position is able to be decided from a predetermined object, when the electronic control unit recognizes that the predetermined object exists in front of the vehicle, the predetermined object indicating that the vehicle needs to be decelerated, the electronic control unit being configured to perform a first assist as the deceleration assist when the electronic control unit determines that the target position is not able to be decided, the first assist being an assist by which the vehicle is decelerated at a first deceleration, the first deceleration being changed based on a brake operation by a driver, wherein an initial value of the first deceleration is a sum of a deceleration that is demanded by the brake operation at a time point of start of the brake operation and a deceleration that is generated in the vehicle at the time point due to the deceleration assist, and the electronic control unit being configured to perform a second assist as the deceleration assist when the electronic control unit determines that the target position is able to be decided, the second assist being an assist by which the vehicle is decelerated at a second deceleration, the second deceleration being equal to or higher than a predetermined deceleration necessary to decelerate the vehicle to the target velocity before the vehicle reaches the target position decided from the predetermined object.