日本民法における連帯債務規定の改正 - 相互保証理論による批判的検討 -

In this paper, we discuss the absolute effects of “joint and several obligations”. Articles 434 to 439 of the Japanese Civil Code provide that (i) a right of set-off invoked by other joint obligors and a release and completion of prescription between the obligee and one of joint obligors shall be effective, to the extent of his/her portion of the obligation, for the benefit of other joint obligors and (ii) that request for performance, novation and merger between an obligee and one of joint obligors, and a set-off invoked by one of joint and several obligors shall be effective for the benefit of all joint obligors. These provisions are considered to be the rules of the “absolute effects” of joint and several obligations. Other things, such as attachment, provisional seizure, a release of solidarity, and so forth have no effect for the other oblegors and have only relative effects (the principle of relative effects is set forth on article 400 of the Japanese Civil Code). In discussions on the Japanese Civil Code Reform (Law of Obligations), however, these provisions on the absolute effects of joint and several obligations may be totally changed to have relative effects. But such changes may lead to theoretical confusions. What if a release of one of the joint obligors has only relative effects to others? As described below, the released obligor would be put in an uncertain situation: a release by the obligee but a claim for reimbursement by the other obligors. In the draft of the interim report for the Civil Code (law of obligations) Reform, article 437 of Japanese Civil Code, titled as “Releases of One Joint and Several Obligor”, is suggested to be changed as follows (tentative translation by the present writer). “In case the obligee releases one joint obligor and manifests an intention that the release will also be effective to the benefit of the other joint obligors, such intention shall prevail. Even if the released obligor offers reimbursement in accordance with the claim of other obligor who made performance of the obligation, he/she cannot have the obligee reimburse for the sum paid.”According to this draft, the obligee’s release has only the relative effect to the other obligors and in case one joint obligor performs the obligation, he/she would have a right to obtain the reimbursement to all the other co-obligors including the released obligor. Such an effect would be insufficient in co-obligors protection. In conclusion, we made clear, in this paper, that each joint obligor is at once a principle obligor and a jointly liable guarantor on behalf of the other co-obligors. Therefore a release of one joint obligor releases all to the extent of his/her portion of the obligation in accordance with the appurtenant nature of guarantee obligations.