The defendant's remaining grounds of appeal are dismissed, and the costs of appeal against this dismissed are assessed against the defendant.

According to the reasoning of the judgment below, the court below rejected the defendant's defense that the contract of this case entered into between the plaintiff and the defendant was terminated on February 25, 1982, and that there was no dispute between the parties, and that the defendant agreed on the return of the overdue rent and electricity rental fee, the amount of KRW 301,797, KRW 2,679,947, which was deducted by the defendant from the overdue rent and electricity rental fee, and the order of the above leased building was also simultaneously performed.

In light of the records, the plaintiff alleged that the date of termination of the lease agreement of this case was February 25, 1982, and it is clear that the defendant argued that the date of termination of the contract of this case was February 7, 1982, and therefore, it would be wrong that the agreement was concluded in February 25, 1982, and therefore, it would be judged as if there was no dispute about the conclusion of the judgment of the court below in this case. However, this point does not affect the conclusion of the judgment of the court below in this case, and there is no reason to dispute this point. In addition, in rejecting the simultaneous performance defense, the court below's evidence preparation process is just, and there is no error of finding the evidence by violating the rules of evidence or failing to exhaust all necessary deliberations, such as

2. We examine both the grounds of appeal Nos. 2 and 3.

According to the reasoning of the judgment below, the court below acknowledged the fact that the defendant continued to occupy the above underground room, which is the object of lease, even after the termination of the lease contract in this case, and ordered the payment of the rent in proportion to the rate of KRW 400,000 per month from February 26, 1982, which is the following day of the termination of the lease contract in this case, since the defendant occupied the above underground room, thereby gaining profits equivalent to the rent in this case without any legal ground, and thereby causing damage to the plaintiff.

However, since "profit in return of unjust enrichment on the ground of benefit without any legal ground" refers to a substantial benefit, it cannot be deemed that a substantial profit was obtained if a building was occupied and used without any legal ground, even if it was not used or used (see Supreme Court Decision 78Da2500, 2501, Mar. 13, 1979; Supreme Court Decision 81Da378, Nov. 10, 1981).

According to the evidence Nos. 1-2 and 5-2 of the above evidence Nos. 1-2 without dispute in the establishment, the plaintiff himself submitted a report on the suspension of the business of the above underground room operated by the defendant on February 7, 1982 to the chief of the competent tax office, and the defendant did not make any profit by suspending multiple businesses in the above underground room after February 8, 1982 and making any correction to the entrance. However, without any judgment as to the relation of evidence as above, the court below acknowledged the defendant's possession of the above underground room and ordered the return of the profit by recognizing the above underground room's profit and ordering the return of the profit. It does not constitute a misunderstanding of the legal principles as to the return of unjust enrichment or a misunderstanding as to the omission of evidence judgment, and it constitutes a ground for reversal under Article 12 (2) of the Act on Special Cases concerning the Promotion, etc. of Legal Proceedings.

3. Therefore, the part of the judgment of the court below against the defendant regarding the claim for restitution of unjust enrichment shall be reversed, and that part of the case shall be remanded to the Seoul High Court. The defendant's remaining appeal shall be dismissed, and the costs of appeal as to this dismissed part shall be assessed against the losing party

Justices Lee Lee Sung-soo (Presiding Justice)