Traumatic cardiac tamponade must be treated by pericardial drainage as soon as possible. We recently encountered a rare case of traumatic cardiac tamponade in which the pericardial fluid disappeared spontaneously immediately before the planned drainage. This case is reported in this paper. The patient was a 22-year-old male who was transported to our hospital after he sustained injuries in a traffic accident. The patient was diagnosed to have a facial bone fracture, bilateral lung contusions, myocardial contusion (suspected), injury to the spinal cord at the L3-L4 level, injury to the left kidney and pelvic fracture. After TAE was performed to deal with the bleeding from the injured pelvis, the patient was immediately hospitalized. About 6 hours after the injury, pericardial fluid accumulation began to be noted, and about 18 hours after the injury, the patient went into shock, responding poorly to fluid resuscitation and treatment with pressor agents. At this time, a diagnosis of cardiac tamponade was made and emergency operation was arranged for. However, just before this could be executed, the patient's blood pressure showed a sharp rise, accompanied by disappearance of the pericardial fluid. He continued to show steady improvement and could eventually be discharged from the hospital.