A cover open mechanism of a dual-bearing reel includes a frame, a first side cover, a spool support portion and a cover opening and closing portion. The cover opening and closing portion includes a cover opening and closing structure and an urging member. The cover opening and closing structure is engaged with the spool support portion and the first side cover, and sets an opened/closed state of the first side cover. The urging member is disposed between the first side cover and the cover opening and closing structure, and urges the first side cover in an openable state. The first side cover is configured to be prevented from rotating when any one of the first side cover and the spool support portion is engaged with the other of the first side cover and the spool support portion.對於雙軸承捲線器,可以將蓋部容易地開放,提高對於內部構造的操作性及作業性。雙軸承捲線器(10)的蓋開放機構(50),是具有:框架(17)、及第1側蓋部(18a)、及捲筒支撐部(15)、及蓋開閉部(16)。蓋開閉部(16),是具有蓋開閉構造(36)及推迫構件(37)。蓋開閉構造(36),是卡合於捲筒支撐部(15)及第1側蓋部(18a),設定第1側蓋部(18a)的開閉狀態。推迫構件(37),是被配置於第1側蓋部(18a)及蓋開閉構造(36)之間,將第1側蓋部(18a)可開放地推迫。第1側蓋部(18a)及捲筒支撐部(15)的其中任一方,是藉由卡合於第1側蓋部(18a)及捲筒支撐部(15)的其中任另一方,使第1側蓋部(18a)被止轉。14‧‧‧捲筒15‧‧‧捲筒支撐部19‧‧‧裝卸部19b‧‧‧操作調整鈕20b‧‧‧煞車塊27b‧‧‧筒狀部35b‧‧‧制動器收納部35d‧‧‧抵接部36‧‧‧蓋開閉構造38‧‧‧擺動構件38c‧‧‧切口部40‧‧‧連結構件41‧‧‧第1連結構件41a‧‧‧孔部41b‧‧‧卡止孔42‧‧‧第2連結構件47‧‧‧小螺釘115e‧‧‧窗部118d‧‧‧制動操作部