With the rise of professional sports industry, spectator injury accidents are occurring more frequently and liability for the accidents has emerged as an important legal issue. In particular, liability issues from sports accidents occurring naturally in the game process due to the risks inherent in the sports brought sharp confrontation of interests between injured spectators and game organizers. The United States as a country with a long history of professional sports has developed the legal principles concerning spectator injuries through numerous cases. Under the common law system the court can view the liability of sports organizers in accordance with the negligence liability under the tort law. Considering spectators who purchase tickets for the game as business invitees, it can be claimed to impose landowner s liability on the game organizer. Prior to 1950, some precedents considered game organizers have landowner s liability. However, they were only for hockey games, and other sports, including baseball, limited the liability of game organizers according to the Baseball Rule. This Rule specifies that on the condition that if the game organizers provided screening in the back of the home plate so that as many spectators as may reasonably be expected to request them on an ordinary occasion can watch the game safely, the game organizers are not liable for spectator injuries. The Rule has been used in the states that adopt the primary assumption of risk as a defence. Since the contributory negligence also bars the plaintiff’s claim for damages when the plaintiff’s negligence influences on the loss, traditionally court has allowed plaintiff as a defence to either choose one of the primary assumption of risk or the contributory negligence or to claim both. However, the primary assumption of risk and the contributory negligence received criticisms for being too unfavorable to the defendant. As a result, even though the plaintiff has assumed the risk, the secondary assumption of risk appeared that claims the duty of care for the plaintiff rests on the defendant and if these duties are violated the defendant’s liability is acknowledged. With the comparative negligence, the liability is relatively recognized to each according to the plaintiff’s and the defendant’s negligence. Recently, the secondary assumption of risks and the comparative negligence are adopted in almost every jurisdictions state in the United States, through limiting the so far Baseball Rule or adjusting its contents. For example, the state court of California restricted the application of Baseball Rule by judging, defendants generally have no legal duty to eliminate risks inherent in the sport itself, but do have a duty to use due care not to increase the risks to a participant over and above those inherent in the sport.”In our case, in the case of spectators injury which result from the risks inherent in the sport, liability of structures possessors and breach of spectator contract can be firstly alleged, and towards the local government which can be recognized as an owner of stadium, liability of structures’ owner and liability on the State Compensation Act can be insisted. On the other hand, as counter-argument of the defendant, a piece of illegality followed by the assumption of risk and comparative negligence can be asserted. We do not have many judgments on spectators’ accidents, and no opinion of courts had presumed the liability for damages on the organizer of sports event. What the legal circumstances of the United States imply is the shift of the legal principles for spectator’s safety. The adaptation of the legal principles is also required on us, which emphasizes the benefit and protection of the law on the human life and health, and reasonable apport