A fastener is capable of fastening a flexible elongated member to a support without the need of a hinge, and can be formed with a small, simple die having a two-surface configuration. In a fastener 1, a long, slender main holder 6 of a length commensurate with the support, two auxiliary holders 7 which extend transversely from opposite ends of the main holder, and engagement arms 9 which form extensions, respectively, from the auxiliary holders, and are attached to the support so as to straddle the support, are formed integrally of synthetic resin. In the main holder 6 and the auxiliary holders 7, are provided guides 13 to 15 which form a channel having a U-shaped cross section which can accommodate the elongated member 2 by the latter being pushed therein. Elastic pawls 17 to 19 can retract so that accommodation is possible when the elongated member is pushed into the channel, and then prevent the elongated member from slipping out from the channel.