PURPOSE: To obtain a good connecting strength by boring a hole of a specific diameter in a crosstie, and plugging a stopper with a polygonal section with the diameter of the circumcircle larger than the diameter of the cut hole and with the diameter of the inscribed circle smaller than the diameter of the hole, through an adhesive.

CONSTITUTION: A hole 3 of a diameter d1 is bored around hole of a crosstie where a dog spike is removed. And a stopper plug 2 with a polygonal section with the diameter d2 of its circumcircle A larger than the diameter d1 and the diameter d3 of its inscribed circle B smaller than the diameter d1 is prepared, an adhesive which consists of a hardening type resin is spread on the stopper plug 2 and the hole 3, and the plug 2 is inserted to the hole 3. Since clearances 4 are generated between the polygonal surface 21 of the plug 2 and the inner wall surface 31 of the hole 3 in this case, the adhesive is not squeezed out. As a result, a specific joining strength of the stopper plug to the cut hole can be obtained.