Supreme Court of Japan, Heisei 26 (O) No. 1023 Damages Claim Case
This case concerned a challenge to Article 750 of the Civil Code, which provides that “a husband and wife shall adopt the surname of either the husband or the wife at the time of marriage.” The appellants sought damages from the State, arguing that this rule violated Article 13 (respect for the individual), Article 14(1) (equality before the law), and Article 24 (equality of the sexes in marriage) of the Constitution. The Supreme Court held that the freedom not to change one’s surname at marriage could not be recognized as a constitutional right under Article 13, and therefore the provision was constitutional. Regarding Article 14(1), the Court found that the Civil Code leaves the choice of surname to agreement between the couple and does not impose legal treatment based on sex, so it was not discriminatory. Finally, under Article 24, the Court ruled that the provision could not be considered unreasonable in light of the principles of individual dignity and essential gender equality in marriage, and therefore did not violate the Constitution.
本件は、民法750条（「夫婦は、婚姻の際に定めるところに従い、夫又は妻の氏を称する」）が憲法に違反するとして、上告人らが国に対して損害賠償を求めた事案である。上告人らは、同条が憲法13条（個人の尊重）、14条1項（平等原則）、および24条（婚姻における両性の平等）に反すると主張した。最高裁判所は、氏の変更を強制されない自由は憲法13条に保障される人格権の一内容とまではいえないと判断し、違憲性を否定した。憲法14条1項については、民法750条は夫婦間の協議に委ねており、性別に基づく差別的取扱いを定めるものではないと判断した。憲法24条についても、個人の尊厳と両性の本質的平等の要請に照らして合理性を欠く制度ではないとし、違憲性を否定した。