To assist a driver of a vehicle in properly determining an inter-vehicle distance.SOLUTION: A driving assist controller includes a passing-along determination unit 55 that determines whether the situation makes it hard for a first vehicle to pass along a second vehicle, a transmission control unit 58 that, when the passing-along determination unit 55 determines that the situation makes it hard for the first vehicle to pass along the second vehicle, serves as a passing-along notification transmission control unit which transmits a passing-along notification, which signifies that the first vehicle intends to pass along the second vehicle, to the second vehicle, a result-of-decision acquisition unit 56 that, after the transmission control unit 58 transmits the passing-along notification, serves as a result-of-movement enabling/disabling decision acquisition unit which acquires from the second vehicle a result of movement enabling/disabling decision that includes information representing a relative positional relationship between the second vehicle and a traveling road on which the second vehicle is traveling, and that signifies whether movement of the second vehicle is enabled or disabled in order to preserve a space where the first vehicle passes along the second vehicle, and a display control unit 59 that serves as a result-of-movement enabling/disabling decision display control unit which displays the result of movement enabling/disabling decision acquired by the result-of-decision acquisition unit 56.SELECTED DRAWING: Figure 2

【課題】車両の運転者が車間距離を適切に判断することを支援する。【解決手段】第一車両が第二車両の周囲をすり抜け困難な状態であるか否かを判定するすり抜け判定部５５と、すり抜け判定部５５がすり抜け困難な状態であると判定した場合、第一車両が第二車両の周囲をすり抜けしたいことを示す、すり抜け通知を第二車両に送信するすり抜け通知送信制御部としての送信制御部５８と、送信制御部５８によってすり抜け通知を送信した後、第二車両から、第二車両と第二車両が走行している走行道路との相対的な位置関係を示す情報を含み、第一車両のすり抜けのスペースを確保するための第二車両の移動の可否の移動可否判断結果を取得する移動可否判断結果取得部としての判断結果取得部５６と、判断結果取得部５６が取得した移動可否判断結果を表示する移動可否判断結果表示制御部としての表示制御部５９とを備える。【選択図】図２