A flip-up apparatus is provided to lift up a hood of a vehicle. The apparatus includes a hinge device for the hood rotatably mounted on a vehicle body and an actuator for lifting up a hood at a vehicle collision. The hinge device has a first and a second arm supporting the hood rotatably to a frame member of the vehicle body and first and second lock plates rotatably supported on the under face of the hood to hold an active part of the actuator. In the upward movement of the active part of the actuator, the active part is held by the lock plates.