(1) Western clothes became more popular than ever in Japan; (2) there brought about a tendency to deny the previous culture because of the loss of the war, and, to make the matter worse, the fundoshi was something the military forced them to wear; (3) because of the advancement of industrialization, people moved from agricultural communities to urban areas to change the traditional family form to a nuclear family, and thus it made it hard to continue the culture in which wearing fundoshi was often symbolically celebrated as a rite of passage to be a grown-up man; (4) as women were encouraged to participate in society, household chores were simplified and thus the time for sewing fundoshi at home became limited; (5) manufacturers of fundoshi were practically decreased and it made it hard for people to get fundoshi at stores; and (6) new types of undergarments, such as a brief type and a trunks type of underpants, appeared at low prices, those functional, and were seen fashionable, undergarments became popular mainly among young people.
日本人の洋装化が一段と進んだこと、敗戦で軍隊で強制されていたことの嫌悪感から旧文化が否定される風潮になったこと、日本の工業化の進展で農村部から都市部に人口の移動が起こり、核家族化が進行して「褌祝」の私的祭事に象徴される褌継承の文化が断絶したこと、女性の社会進出で家事が簡略化されて自家で縫製する機会がなくなったこと、製造販売する業者も少なく店頭に並ばず、入手性に難があったこと、ブリーフ、トランクス等の新しい下着が廉価で出現して、機能性だけでなくファッション性のある下着が若者を中心に普及したことなどである。