To provide a locking piece capable of deciding an accurate position with blind touch by the feeling of finger tips, and capable of easily attaching to clothes at home an engaging tool with a hook-and-loop fastener which can be fixed by pressure.

A hook-and-loop fastener 2 is fixed to a thin plastic substrate 5 with affluent rigidity. Locking pieces are fixed to two basic materials, respectively, fitted, and rotated so as to press a hook-and-loop fastener part by using a concave locking piece 1 in which folding fan-shaped holes 3 are provided on the substrate, and a projecting locking piece 7 provided with projecting parts 8 opposing thereto and fitted to the holes of the locking piece. Thus, engagement of a fly of clothes without position displacement is completed. The process for mounting both of the locking pieces on the base materials such as clothing materials is set so that the hook-and-loop fastener is protruded from the base material to be fixed by sewing at home. An outlet seam is provided at a substrate peripheral rim. In addition, sewing holes for preventing the hook-and-loop fastener from rising. Therefore, fixing to the clothing materials is facilitated by sewing with a needle and thread at home.