PURPOSE: To provide a tunnel entrance shut-off device which can safely, quickly and automatically shut off a tunnel entrance gate in order to prevent the secon dary disasters when an accident of vehicles occurs in a tunnel.

CONSTITUTION: Plural information display panels 3 are placed at 8 tunnel entrance and also at other points ahead of the entrance. Then a gate 4 is prepared et the entrance to automatically shut off the entrance together with an ITV camera 5 which monitors the vehicles running at the points near the entrance, and a controller 6. When an accident occurs in the tunnel, an accident occurrence signal is received by the controller 6 and the information on the accident is displayed on the panels 3 via the controller 6. Then the controller 6 decides a state where the vehicles never collide against the gate 4 although it is shut off based on the image data acquired through the camera 5. Then the controller 6 outputs a gate shut-off signal to the gate 4 to shut it off.