Dynamic fracture behavior caused by the out-of plane loading is evaluated by the method of caustics. Out-of plane displacement is measured by the C.G.S. method under static loading and it is in good agreement with theoretical one. Diameter of caustic pattern formed by the out-of plane loaded plate is compared with that one calculated by the theoretically induced formula. Dynamic fracture testing apparatus is assembled with the ultrahigh-speed camera, and caustic pattern under dynamic loading is obtained. Moreover, dynamic fracture characteristics of PMMA plate are discussed.