A travel assistance device comprising: surrounding environment imaging means for obtaining a captured image that captures a surrounding environment of a vehicle by an imaging device having a start point of a driver's line of sight and an optical axis corresponding to a driver's line-of-sight direction; connecting road identifying means for identifying, based on the captured image and map information of an area around the vehicle, a location where a connecting road is present in the captured image , the connecting road being a road connecting to a traveling road of the vehicle at a divergence point present around the vehicle; visibility determining means for determining driver's visibility of the connecting road, based on a positional relationship between the location of the connecting road and a location of an obstacle present around the vehicle in the captured image ; and output means for outputting a result of the determination made by the visibility determining means, characterized by comprising determination region setting means for setting a determination region in a region including at least a part of the connecting road in the captured image , the determination region serving as a target for determining the visibility of the connecting road, wherein the visibility determining means is configured to determine the driver's visibility of the connecting road , based on a positional relationship between the connecting road and the obstacle in the determination region , and wherein the determination region setting means is configured to set the determination region in a region including a road portion of the connecting road within a predetermined distance along the connecting road from an end portion connecting to the divergence point . surrounding environment imaging means for obtaining a captured image that captures a surrounding environment of a vehicle by an imaging device having a start point of a driver's line of sight and an optical axis corresponding to a driver's line-of-sight direction; connecting road identifying means for identifying, based on the captured image and map information of an area around the vehicle, a location where a connecting road is present in the captured image , the connecting road being a road connecting to a traveling road of the vehicle at a divergence point present around the vehicle; visibility determining means for determining driver's visibility of the connecting road, based on a positional relationship between the location of the connecting road and a location of an obstacle present around the vehicle in the captured image ; and output means for outputting a result of the determination made by the visibility determining means, characterized by comprising determination region setting means for setting a determination region in a region including at least a part of the connecting road in the captured image , the determination region serving as a target for determining the visibility of the connecting road, wherein the visibility determining means is configured to determine the driver's visibility of the connecting road , based on a positional relationship between the connecting road and the obstacle in the determination region , and wherein the determination region setting means is configured to set the determination region in a region including a road portion of the connecting road within a predetermined distance along the connecting road from an end portion connecting to the divergence point . <EOS>