An impact test apparatus includes a holding device for holding a test piece at an arbitrary holding force, an impact applying device for applying an impact force to the test piece held by the holding device, a force sensor for sensing the impact force applied to the test piece by the impact applying device, a high-speed camera for detecting a displacement of the test piece when applied with the impact force by the impact applying device, and an output device for synchronizing a signal from the force sensor with a signal from the high-speed camera and outputting an impact stress-strain characteristic curve when the impact force is applied to the test piece.