Transaction per standard contract terms plays very important role in everyday life of the people. The current society is mass consumption society. Therefore, standard contract terms play very important role in modern consumer society. In other words, standard contract terms has important roles in modern, mass product society, especially in the field of insurance and banking business. But the interest of the clients can be neglected by the unfair standard contract terms. According to civil law(§ 137 Korean Civil Code) partial invalidity leads to total invalidity. But the interest of the consumer can be neglected, when we adopt it in its integrity in the field of standard contract terms. Therefore § 16 korean unfair contract terms act regulates its exception. That is, partial invalidity leads not to total invalidity, but the contract itself is valid. When it is too severe, then the contract totally invalid. Through it korean unfair contract terms act protect the consumer. It happens very often that people confront problems with the use of inadequate standard contract terms. One of the rule about regulating standard contract terms is the special rule of partial invalidity. The special rule of partial invalidity is regulated in § 16 korean unfair contract terms act. It is also regulated in § 306 German Civil Code. The rule is therefore a kind of global standard. The court decisions in korea have some problems in the field of the application of this rule. It should apply the rule more clearly and definitely. Of course, the special rule of partial invalidity should be also applied in insurance contracts. Insurance contracts have some special character. Nevertheless, the standard contract terms of insurance is also a kind of standard contract terms. The special character of insurance contracts should not be pointed out so severely in modern society. This is also international trend. We can not adopt the rule of maintaining reduction that is discussed in germany. It can arrogate the purpose of the korean unfair contract terms act. The exception of § 16 korean unfair contract terms act should be bowed to with discretion and very strictly.