To improve the brushing ability of a channel-shaped brush by improving the expansibility of bristles, securing the crossing condition and tightness of the tops of bristles between rolls when bristles are tightly wound around roll shafts, preventing generation of brush marks caused by the unevenness of bristles between the rolls and increasing bristles to be planted.

In this channel-shaped brush, a core material 1 made of a double-folded strip is inserted into the interior of the folded base of a double- folded bristle tuft 2, and the folded base of the double-folded bristle tuft 2 together with the core material 1 is clasped by a gutter-shaped channel 3 from outside. The upper part of each side plate 4 of the double-folded strip constituting the core material 1 is made to project higher than the upper edge 6 of each side plate 5 of the channel 3 in the longitudinal direction, and nail pieces 8 extending at intervals from the upper edge 6 of each side plate 5 of the channel 3 are erected along a side plate part 7 extending from each side plate 4 of the core material. The tops of the nail pieces 8 are bent into the inside between the side plates 4 of the core material 1.