The suitability principle introduced by the Capital Market and Financial Investment Business Act (hereafter, the Capital Market Act) to protect investors, has been included in the Insurance Business Act. The suitability principle means: before a policyholder concludes an insurance contract, the insurance company or a person engaged in insurance solicitation must understand matters prescribed by the Presidential Decree, such as the age and property status of the policyholder, the reason the policyholder is buying insurance, and other relevant matters by interviewing or questioning the policyholder. (Insurance Business Act Article 95) And the Presidential Decree of the Insurance Business Act limits the suitability principle to apply only to the variable insurance. [same Decree 42-3 (2)]Variable insurance is an insurance in which the whole or portion of the premium paid by the ordinary policyholder is included in the special account of the insurer, and invested mainly in stock or marketable securities; afterwards the insurer pays out applicable proceeds to the insured by revenues derived from the foregoing investment. Therefore, the insurance has the dual characteristics of insurance and investment instrument, which has induced the suitability principle to be stipulated in the Insurance Business Act. The recent case relating to the variable universal life insurance is significant, as it is the first case referring to the suitability principle concerning variable insurance. But the decision has some arguable points, such as confusing the duty to explain with the suitability principle, and failing to assess the amount of damages.The suitability principle in variable insurances encompasses the duty of classifying the policyholder(only for the ordinary policyholder), duty to confirm the customer, duty to fully understand the respective products, judging suitability, soliciting appropriate products, and maintaining and managing related information. Especially, the method and criterion in deciding the suitability of a product need to be stipulated in Insurance Business Act or Presidential Decree of the Act. The differences in applying suitability to soliciting the insurance comparing with soliciting the investment instrument needs to be researched, as different financial products have different traits concerning the needs of the customer, the object of contract, the main philosophy of the rule governing those products etc.; and the differences, if any, need to be stipulated within the Insurance Business Act and the Presidential Decree of that act.