To provide a high-speed acceleration device that can restrain variations of specimen speed and a crash position to a body to be crashed even if the specimen is a plate having a curved shape and can crash the specimen into the body to be crashed while maintaining a fixed posture, and to provide a crash testing device using the high-speed acceleration device.

The high-speed acceleration device includes: a sabot for storing a specimen inside; an accelerating tube that has a through-hole in an axial direction and is filled with the sabot so that the accelerating tube can travel in the through-hole; an acceleration device for accelerating the sabot by supplying compressed gas to the accelerating tube; and a stopper that is installed at a downstream end of the accelerating tube for crashing the sabot for stopping. The high-speed acceleration device accelerates the sabot for storing the specimen in the accelerating tube and stops the sabot by the stopper, thus separating the specimen from the sabot by inertia for discharging to the outside of the accelerating tube. In the high-speed acceleration device, the specimen is a plate having a curved shape, the sabot is made of foamed polystyrene, and the sabot has a storage section that has an opening on the front and inserts and supports the specimen for storage.