A spool for a dual-bearing reel is rotatably disposed in a reel body. The spool includes a bobbin trunk, a first flange and a second flange. The bobbin trunk enables a fishing line to be wound about an outer periphery thereof. Each of the first and second flanges includes an inner wall surface and an outer peripheral surface. The inner wall surface is provided on one end of the bobbin trunk. The outer peripheral surface extends axially outward from a distal end of the inner wall surface. Additionally, the distal end of the inner wall surface of the first flange has a larger outer diameter than the distal end of the inner wall surface of the second flange. The inner wall surface of the first flange and the outer peripheral surface of the first flange are connected through a smooth curved surface.