The Flower Nagai Line (フラワー長井線, Furawā-Nagai-sen) is a Japanese railway line in Yamagata Prefecture, Japan. It connects Akayu Station in Nanyō to Arato Station in Shirataka. The Flower Nagai Line is the only line operated by the third sector Yamagata Railway Company (山形鉄道, Yamagata Tetsudō), which took over the former JR East line in 1988.