PURPOSE: To quicken the work of finishing a joint part, by a method wherein the thickness of a bar-shaped joint-sealing member made of thermoplastic resin is made thinner than the width of the joint part, the height thereof is made higher than the depth of the joint part, and the length thereof is arbitrary.

CONSTITUTION: A joint-sealing member is so composed that a thickness 2 of a main body 1 is made thinner than the width of a joint part 6, that a height 3 thereof is made higher than the depth of the joint part 6, and that a length 4 is made in a free size. When the joint-sealing member with the thickness 2 enabling insertion into the joint part 6 between concrete parts 5 is inserted thereinto, the upper part of the joint-sealing member with the height 3 slightly higher than a depth 7 of the joint part 6 becomes so as to slightly protrude from the surfaces of the concrete parts 5. After that, a hot iron is applied to the upper part of the joint-sealing member, the joint-sealing member is allowed to melt, and the whole thereof is allowed to melt. In this way, by only a sheer method wherein the upper part of the joint-sealing member is heated with the hot iron, the joint-sealing member is melted and then solidified, and the work of finishing the joint part 6 can be quickened.