In a few very extreme cases, courts may "pierce the corporate veil," and hold some or all of the shareholders personally liable for the corporation’s debts. This is the so-called doctrine of piercing the corporate veil. This doctrine was first developed at the end of 19th century in America. Under the American corporate law, if the corporation’s shares are held by individuals, courts look in deciding whether to pierce the corporate veil to such factors as, for example, tort vs. contract, fraud, inadequate capitalization and failure of formalities. In nearly all cases, at least two of the above four factors must be present for the court to pierce the veil; the most common combination is probably inadequate capitalization plus failure to follow corporate formalities. In Japan, the doctrine of piercing the corporate veil was first adopted in 1969 by a Supreme Court decision, which categorized the piercing the corporate veil cases into two groups; one is abuse of corporate legal entity case and the other one is skeletonizing of legal corporate entity case. Thereafter all the Japanese courts are following the Supreme Courts' lead and categorize the piercing the corporate veil case as above. However, this kind of categorization has been strongly criticized by many Japanese scholars because the factors to be considered in determining which cases belong to the abuse of corporate legal entity case and which cases belong to the skeletonizing of legal corporate entity case are too vague. Such categorization is the only creature of Japanese courts and American courts never know such a dichotomy. Even though the doctrine of piercing the corporate veil applied by the Japanese Courts has many problems as mentioned above, Korean courts and scholars followed the Japanese Courts's attitude without much thought. The object of this article is to study the American doctrine of piercing the corporate veil which is the model of korean and japanese doctrine of piercing the corporate veil, and to reasonably reconstruct the system of Korean doctrine of the corporate veil.