Abstract: This invention depicts a web winding apparatus for winding belt-like materials (webs) such as plastic films, paper, thin metallic strips, which are slit to a predetermined width by a slitter. This web winding apparatus has at least one winder unit detachably mounted to a main body of winding apparatus. The or each of the winder units includes a support beam detachably mounted to the main body of winding apparatus, a plurality of pairs of arms provided on the support beam, for holding reels to wind slit webs from opposite sides and winding tension generators provided on the support beam corresponding in number to the reels, for giving a winding tension to the reels. A plurality of winder units are prepared in advance having the aforesaid arrangement, having various arm intervals arranged to accommodate to the widths of the slit, whereby winder units corresponding to the widths of webs are mounted to the winding apparatus.