産屋が利用されなくなって久しい。産屋が遅くまで残った地域でも昭和三〇年代がおおむね終焉時期となっている。産屋習俗の終焉の要因は一様ではない。本研究のテーマは、なぜ産屋習俗は終焉を迎えたのかという根源的な問いである。私たちは、産屋とは主屋と別に小さな建物を建て、そこに産婦が血の穢れのために家族と隔離されて食事も別にする施設であると学び、産屋を穢れからの隔離・別火というステレオタイプ化された視点で認識してきた。しかし出産の穢れからの隔離・別火が所与のものでないとすれば、産屋の本質はいったいどこにあるのであろうか。本論文が産屋習俗の終焉過程に注目する理由の第一点は、現在（＝平成二〇年代）が産屋体験者から直接話を聞ける最後の機会であること。産屋体験者からの聞き書きは緊急性を有し詳細な記録化が望まれる。第二点は産屋の終焉から過去に遡れば当該地域における産屋の変遷過程を明らかにできると考えた。現時点で伝承者からきちんと聞き書きを行うことは重要であり、産屋習俗の終焉過程の研究にも資するのである。先行研究では、産屋の発生は神の加護を得る籠もりにあるとされる。牧田茂・高取正男・谷川健一の所説は、産屋の原初的形態に視点を置いた論理である。実際に原初的形態を彷彿とさせる民俗事例が各地に伝承されているが、それをもって現行習俗を古代へ飛躍させるのは論理的に危険が伴うであろう。事例で取り上げた山形県小国町大宮のコヤバは、明治二二年以前は出産の都度小屋を建てていたが、警察署長の意見で常設のコヤバになったとされる。仮設から常設へ変化する傾向は、福井県敦賀市池河内の事例からも明らかである。福井県敦賀市白木のサンゴヤは、昭和五〇年代まで使用されており全国で最も遅くまで利用されていた。常設化の産屋は伝統を守りながらも、滞在期間の短縮化、休養の場の拡大化など、地域に応じた多様なあり方をみせている。The custom of using ubuya (delivery huts) has been extinct for years. The regions where it survived for the longest time also saw it dying out from the late 1950s to the early 1960s. The reasons why this custom lingered for a long time vary depending on the region. This paper addresses a fundamental question of why the custom of using ubuya died out. People were taught that ubuya meant a small hut built separately from the main house to isolate a pregnant woman from her family and prepare meals separately to contain defilement by blood; therefore, many people had a stereotype perspective that ubuya should be used for isolation and separate meal preparation to contain impurity by childbirth. However, if the isolation and separate meal preparation were not a matter of course, what was the essence of ubuya?There are two reasons why this paper focuses on the process of dying out of ubuya. The first one is because we will never have a chance to interview those who have experienced it if we pass up this opportunity now (in the 2010s). It is urgent to put such experiences on record based on firsthand oral recollections. The more detailed the record is, the more useful it would be. The second reason is because if we go back into the history of ubuya, we could reveal the changes in the custom in the region. It is very important to interview those who directly involved and record their experiences now. The results can contribute to the research of the process of dying out of ubuya.Previous studies suggested that ubuya had been originated from seclusion to pray for divine protection. The theories of Shigeru Makita, Masao Takatori, and Kenichi Tanigawa focused on the original form of ubuya. In fact, folk customs resemble to the original ones have been handed down in various regions. It is, however, illogical to link modern customs to ancient ones just because they are similar to each other. As referred to in this paper, koyaba in Ōmiya, Oguni Town, Yamagata Prefecture, is said to have been built for temporary use for each and every childbirth before 1889 but transformed into permanent facilities based on the opinion of a police chief. This shift can be demonstrated by another example from Ikenokōchi, Tsuruga City, Fukui Prefecture. In Shiraki, Tsuruga City, Fukui Prefecture, sangoya had been used until the early 1980s, which means this is one of the last regions where the custom lingered on. Permanent ubuya were used, in principle, in a traditional way, but there were regional variations, such as shortening the time of stay and expanding rest areas.