1. A road estimation device configured to receive data including a plurality of core points from an external object, the core points being assigned along a road and being respectively assigned with attributes for identifying the road, the road estimation device further configured to extract links pertinent to the road represented by the core points for estimating the road on a map, the road estimation device comprising: a non-transitory storage medium configured to input map data including links in a unit of a divided region being one of a plurality of divided areas, each of the links having a termination point in a boundary of the divided region, the links respectively having attributes corresponding to attributes of the core points; and a central processing unit (CPU) configured to: when the core points exist beyond a boundary of the divided region, generate a virtual core point being a new core point on the boundary of the divided region in the map data, which the storage medium inputs, and assign an attribute to the virtual core point based on the attributes of the core points; and extract a candidate link being candidate of the road represented by the core points from the map data according to the attributes of the links, the attributes of the core points, and the attribute of the virtual core point, wherein the plurality of core points is received with traffic information including traffic congestion information.