An external environment recognizing device for vehicle comprising: an image acquiring unit configured to acquire an image obtained by picking up an image of an area ahead of an own vehicle; a light-source extracting unit configured to extract a light source from the acquired image; an own-vehicle-speed acquiring unit configured to acquire own vehicle speed; an oncoming-vehicle-presence-possible-region setting unit configured to estimate an oncoming vehicle presence possible region on the basis of the own vehicle speed; and an oncoming-vehicle detecting unit configured to detect an oncoming vehicle on the basis of the oncoming vehicle presence possible region estimated by the oncoming-vehicle-presence-possible-region setting unit and the light source extracted by the light-source extracting unit, characterized in that the oncoming-vehicle-presence-possible-region setting unit estimates the oncoming vehicle presence possible region on the basis of the own vehicle speed, a minimum curvature radius of a traveling road corresponding to a speed limit determined in advance, and traffic information indicating whether driving on the traveling road is driving on a right side or driving on a left side, wherein the oncoming-vehicle-presence-possible-region setting unit estimates a minimum turning radius of the traveling road on the basis of the own vehicle speed, the minimum curvature radius of the traveling road corresponding to the speed limit determined in advance, and the traffic information indicating whether driving on the traveling road is driving on the right side or driving on the left side and estimates the oncoming vehicle presence possible region on the basis of the estimated minimum turning radius (R_min), wherein, when the driving on the traveling road is the driving on the left side, the oncoming-vehicle-presence-possible-region setting unit estimates, as the oncoming vehicle presence possible region, a region further on the right side than a circle drawn in a left curve at the minimum turning radius (R_min) from a right end of the own vehicle, or when the driving on the traveling road is the driving on the right side, the oncoming-vehicle-presence-possible-region setting unit estimates, as the oncoming vehicle presence possible region, a region further on the left side than a circle drawn in a right curve at the minimum turning radius (R_min) from a left end of the own vehicle. an image acquiring unit configured to acquire an image obtained by picking up an image of an area ahead of an own vehicle; a light-source extracting unit configured to extract a light source from the acquired image; an own-vehicle-speed acquiring unit configured to acquire own vehicle speed; an oncoming-vehicle-presence-possible-region setting unit configured to estimate an oncoming vehicle presence possible region on the basis of the own vehicle speed; and an oncoming-vehicle detecting unit configured to detect an oncoming vehicle on the basis of the oncoming vehicle presence possible region estimated by the oncoming-vehicle-presence-possible-region setting unit and the light source extracted by the light-source extracting unit, characterized in that the oncoming-vehicle-presence-possible-region setting unit estimates the oncoming vehicle presence possible region on the basis of the own vehicle speed, a minimum curvature radius of a traveling road corresponding to a speed limit determined in advance, and traffic information indicating whether driving on the traveling road is driving on a right side or driving on a left side, wherein the oncoming-vehicle-presence-possible-region setting unit estimates a minimum turning radius of the traveling road on the basis of the own vehicle speed, the minimum curvature radius of the traveling road corresponding to the speed limit determined in advance, and the traffic information indicating whether driving on the traveling road is driving on the right side or driving on the left side and estimates the oncoming vehicle presence possible region on the basis of the estimated minimum turning radius (R_min), wherein, when the driving on the traveling road is the driving on the left side, the oncoming-vehicle-presence-possible-region setting unit estimates, as the oncoming vehicle presence possible region, a region further on the right side than a circle drawn in a left curve at the minimum turning radius (R_min) from a right end of the own vehicle, or when the driving on the traveling road is the driving on the right side, the oncoming-vehicle-presence-possible-region setting unit estimates, as the oncoming vehicle presence possible region, a region further on the left side than a circle drawn in a right curve at the minimum turning radius (R_min) from a left end of the own vehicle.