A slitter-winder for fiber webs has an unwinding section (10), a slitting section (20) and a winding section (30) and is configured to unwind, slit and wind a thick fiber web having a basic weight of at least 200 g/m.sup.2 to customer rolls (33). The unwinding section (10) has a first unwinder (11) and a second unwinder (12) for unwinding the thick fiber web from a parent roll of full-width thick fiber web (W11, W12), and a joining device (16, 17) for joining a beginning end of a thick fiber web (W11) coming from a parent roll in the first unwinder to an end of a thick fiber web (W12) coming from a parent roll in the second unwinder by forming a joint (J). The winding section (30) has a cutting device (35) for cutting and removing joint part(s) of the thick fiber web from the winding section (30).