1. As to the ground of appeal No. 1, the court below is just in light of the relevant legal principles, where the victim of a traffic accident seeks to pay mutual aid money to the defendant through a lawsuit as to the interpretation of the defendant's mutual aid clause, and where the amount calculated according to the victim's fault ratio is below the amount corresponding to the medical relationship cost, the compensation provision for medical relationship costs cannot be applied to the amount calculated by offsetting the amount calculated according to the victim's fault ratio, and the same applies to the case where the insurer exercises mutual aid claim against the defendant on behalf of the victim who is the insured, and contrary to the defendant's allegation in the ground of appeal, there is no error of law that affected the conclusion of the judgment by misapprehending

2. Regarding ground of appeal No. 2

A. The proviso of Article 3 (1) 2 of the Enforcement Decree of the Guarantee of Automobile Accident Compensation Act provides that where the amount of damage sustained by the victim falls short of the corresponding amount of medical fees calculated according to the standard of medical fees covered by automobile accident insurance under Article 15 (1) of the Guarantee of Automobile Accident Compensation Act, the corresponding amount of medical expenses shall be paid within the scope of the amount prescribed in [Attachment Table 1]. The purport of the proviso of the proviso of subparagraph 2 above is to interpret that even in a case where the amount of damage calculated by deducting the amount equivalent to the ratio of negligence among the damage suffered by the victim of automobile accident falls short of the corresponding amount of medical expenses under the above provision, the corresponding amount of medical expenses shall be deemed as the amount of damage for the victim of automobile accident to guarantee medical treatment of the victim of automobile accident as the liability insurance money. Therefore, the victim of automobile accident may claim that

The liability insurance money payable to a person is jointly assumed by the perpetrator’s liability for damages against the victim of a traffic accident. Of these, the amount of damages is increased compared to the amount of damages that the perpetrator should bear by legal fiction as above (see, e.g., Supreme Court Decisions 2006Da82793, Dec. 11, 2008; 2012Da44563, Oct. 11, 2012).

B. According to the reasoning of the judgment below, with respect to the traffic accident of this case between the insured vehicle (hereinafter referred to as "Plaintiff vehicle") and the defendant's accident of this case between the driver of the plaintiff vehicle, the plaintiff paid 24,924,280 won as insurance money and 20,545,770 won as insurance money and received 11,775,680 won as mutual-aid money from the defendant. In light of the records, it is difficult to find any material that can specifically identify the nature of the insurance money that the plaintiff paid to A, the existence or content of the subrogation agreement between the plaintiff and A, and in light of the above facts, the plaintiff and A compensate for the damage when the plaintiff suffered from the accident of the plaintiff's vehicle, and in light of the above legal principles, it is sufficient to conclude that the insurance agreement was reached to obtain the right of the third party. In light of the above legal principles, the plaintiff has sufficient basis to maintain the identity of the defendant's claim under the proviso to Article 3 (1) 2 of the Enforcement Decree of the Guarantee of Automobile Accident Compensation Act.

Therefore, the court below should first grasp the nature of the insurance money that the plaintiff paid to A, the existence or content of the subrogation agreement between the plaintiff and A, and then examine where the degree of injury of A falls under the category of [Attachment Table 1] under Article 3(1)2 of the Enforcement Decree of the Guarantee of Automobile Accident Compensation Act, determine the limit of the liability mutual aid amount, and examine where the amount of damage calculated by deducting the amount equivalent to the ratio of negligence of A reaches the corresponding amount of the medical fees calculated based on the medical fee standard for automobile accident insurance, and take measures such as recognizing the corresponding amount of the medical expenses as the amount of the liability mutual aid amount, if the amount of damage falls short of

Nevertheless, the court below held that the proviso of Article 3 (1) 2 of the Enforcement Decree of the Guarantee of Automobile Accident Compensation Act shall not apply in cases where the insurer who paid the insurance money to the victim instead of the victim of the instant traffic accident, claims the amount of indemnity on behalf of the victim, who is the insured. In so doing, the court below erred by misapprehending the legal principles on the interpretation of the proviso of Article 3 (1) 2 of the Enforcement Decree of the Guarantee of Automobile Accident Compensation Act

3. Conclusion

Therefore, the lower judgment is reversed, and the case is remanded to the lower court for further proceedings consistent with this Opinion. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Shin Jae-young in charge

Justices Lee Sang-hoon

Justices Kim Gin-young