To provide a fastening tool for an agricultural and horticultural strut by surely fixing the C-shaped fastening tool to be mounted by clamping to the strut from the outside surface of the strut provided with a projection on the outer peripheral surface, not rotating the fastening tool around the strut as a shaft and having nothing to damage plants, etc.

A dented groove 21 which corresponds to a projection 11 made continuously or intermittently in the length direction of the outer peripheral surface of the strut 1 and is formed at a depth and a position corresponding to the projection 11 of the strut 1 or a cavity-like recessed part 22 which corresponds to a great number of regularly formed granular projections on the outer peripheral surface of the strut 1 and is formed at a depth and a position corresponding to the granular projections of the strut 1 are formed on the strut claming and fixing surface of the fastening tool 2.