A driving assistance device for a vehicle, the driving assistance device comprising: a camera configured to obtain a front image of the vehicle; at least one of sensing unit; a processor configured to: obtain, based on the front image, a part of a lane of a road included in a visible area of the front image, wherein obtaining the part of the lane in the visible area comprises detecting the lane in the front image, distinguishing the visible area in the front image from an invisible area in the front image based on the result of detecting the lane, and obtaining a distance from the vehicle to an endpoint of the obtained part of the lane included in the visible area of the front image; detect a plurality of objects around the road through the at least one of sensing unit; determine curvature of road in the invisible area of the front image based on a location of the detected plurality of objects; estimate another part of the lane included in the invisible area of the front image based on the determined curvature in the invisible area of the front image and a width of the road; and generate a guide image in which the lane is divided into the visible area and the invisible area based on the obtained part of the lane in the visible area and the estimated another part of the lane in the invisible area; and an output unit configured to output the guide image; wherein the invisible area is another area other than the visible area, wherein the at least one of sensing unit comprises at least one of a radar module, and a lidar module, wherein the detected plurality of objects is detected by using a radar and/or lidar module, in the invisible area of the front image. a camera configured to obtain a front image of the vehicle; at least one of sensing unit; a processor configured to: obtain, based on the front image, a part of a lane of a road included in a visible area of the front image, wherein obtaining the part of the lane in the visible area comprises detecting the lane in the front image, distinguishing the visible area in the front image from an invisible area in the front image based on the result of detecting the lane, and obtaining a distance from the vehicle to an endpoint of the obtained part of the lane included in the visible area of the front image; detect a plurality of objects around the road through the at least one of sensing unit; determine curvature of road in the invisible area of the front image based on a location of the detected plurality of objects; estimate another part of the lane included in the invisible area of the front image based on the determined curvature in the invisible area of the front image and a width of the road; and generate a guide image in which the lane is divided into the visible area and the invisible area based on the obtained part of the lane in the visible area and the estimated another part of the lane in the invisible area; and an output unit configured to output the guide image; wherein the invisible area is another area other than the visible area, wherein the at least one of sensing unit comprises at least one of a radar module, and a lidar module, wherein the detected plurality of objects is detected by using a radar and/or lidar module, in the invisible area of the front image. obtain, based on the front image, a part of a lane of a road included in a visible area of the front image, wherein obtaining the part of the lane in the visible area comprises detecting the lane in the front image, distinguishing the visible area in the front image from an invisible area in the front image based on the result of detecting the lane, and obtaining a distance from the vehicle to an endpoint of the obtained part of the lane included in the visible area of the front image; detect a plurality of objects around the road through the at least one of sensing unit; determine curvature of road in the invisible area of the front image based on a location of the detected plurality of objects; estimate another part of the lane included in the invisible area of the front image based on the determined curvature in the invisible area of the front image and a width of the road; and generate a guide image in which the lane is divided into the visible area and the invisible area based on the obtained part of the lane in the visible area and the estimated another part of the lane in the invisible area; and an output unit configured to output the guide image; wherein the invisible area is another area other than the visible area, wherein the at least one of sensing unit comprises at least one of a radar module, and a lidar module, wherein the detected plurality of objects is detected by using a radar and/or lidar module, in the invisible area of the front image.