In a spool for dual-bearing reel, deformation of the spool, causing difficulty in its usage, can be prevented while rotation performance of the spool can be highly maintained. The spool (12) includes a tubular bobbin trunk (12b), a pair of flanges (12a) and a boss member (12c). The bobbin trunk (12b) has a peripheral surface extending along the axial direction of the spool (12) so that a fishing line can be wound around the bobbin truck (12b). The peripheral surface of the bobbin trunk (12b) includes thickened wall portions (12d) disposed on opposing sides of an axial center part of the bobbin trunk (12b). The flanges (12a) are integrally formed with the peripheral surface of the bobbin trunk (12b) as a one-piece, unitary member. Each of the flanges (12a) extends substantially in a radially outward direction of the spool (12). The boss member (12c) is disposed between axial ends of the bobbin trunk (12b) and extends along the radial direction of the spool (12). The boss member (12c) includes a disc portion with a through-hole (12f) to receive a spool shaft (16). Each of the thickened wall portions (12d) has a thickness greater than other portions of the bobbin trunk (12b).