A road estimation device configured to receive data including a plurality of core points (CPa, CPb) from an external object, the core points (CPa, CPb) being assigned along a road and being respectively assigned with attributes for identifying the road, the road estimation device further configured to extract links (SL, GL), pertinent to the road represented by the core points (CPa, CPb) for estimating the road on a map, the road estimation device comprising: a map data input unit configured to input map data including links respectively having attributes corresponding to the attributes of the core points (CPa, CPb); a link extraction unit configured to extract candidate links (SL, GL), which are candidate of the road represented by the core points (CPa, CPb), correspondingly to each of the core points (CPa, CPb), from the map data according to the attributes of the links and the attributes of the core points (CPa, CPb), whereby the link extraction unit is configured to set a search region around an object core point among the core points (CPa, CPb) and to extract candidate links inside the search region; and a road estimation unit (17a, S410-S450) configured to implement a road search processing which is configured to: extract a start-side core point (CPa) and an end-side core point (CPb) being adjacent to each other from an array of the core points (CPa, CPb); and search a link pertinent to a road, which connects a start-side candidate link with an end-side candidate link, the start-side candidate link and the end-side candidate link being extracted by the link extraction unit and being respectively corresponding to the start-side core point (CPa) and the end-side core point (CPb), the road estimation unit (17a, S410-S450) being further configured to estimate a road on the map from the start-side core point (CPa) to the end-side core point (CPb) according to the searched link, characterized in that the candidate links extracted inside the search region include a link, which is partially included in the search region and is connected with two end nodes positioned out of the search region. a map data input unit configured to input map data including links respectively having attributes corresponding to the attributes of the core points (CPa, CPb); a link extraction unit configured to extract candidate links (SL, GL), which are candidate of the road represented by the core points (CPa, CPb), correspondingly to each of the core points (CPa, CPb), from the map data according to the attributes of the links and the attributes of the core points (CPa, CPb), whereby the link extraction unit is configured to set a search region around an object core point among the core points (CPa, CPb) and to extract candidate links inside the search region; and a road estimation unit (17a, S410-S450) configured to implement a road search processing which is configured to: extract a start-side core point (CPa) and an end-side core point (CPb) being adjacent to each other from an array of the core points (CPa, CPb); and search a link pertinent to a road, which connects a start-side candidate link with an end-side candidate link, the start-side candidate link and the end-side candidate link being extracted by the link extraction unit and being respectively corresponding to the start-side core point (CPa) and the end-side core point (CPb), extract a start-side core point (CPa) and an end-side core point (CPb) being adjacent to each other from an array of the core points (CPa, CPb); and search a link pertinent to a road, which connects a start-side candidate link with an end-side candidate link, the start-side candidate link and the end-side candidate link being extracted by the link extraction unit and being respectively corresponding to the start-side core point (CPa) and the end-side core point (CPb), the road estimation unit (17a, S410-S450) being further configured to estimate a road on the map from the start-side core point (CPa) to the end-side core point (CPb) according to the searched link, the candidate links extracted inside the search region include a link, which is partially included in the search region and is connected with two end nodes positioned out of the search region.