Abstract: A necktie with a knot-forming core includes a necktie body made of cloth and a knot-forming core made of synthetic resin. The necktie body has a necktie panel having a combining hole at a top portion thereof, a knot-cloth sewed to the knot-forming position of the panel and a pair of combining holes at lower corners thereof, and a pair of necktie-arms sewed to the respective upper corners of the knot-cloth which are used for attaching the necktie to shirts of blouses. The knot-forming core includes a core-body and a combining projection provided on the back of the core-body. A Y-shaped necktie having a desired size and shape is assembled merely by placing the core on the back of the knot-forming position of the necktie-body, and thereafter orderly fitting the above-mentioned three combining holes around the combining projection of the core. The Y-shape necktie thus assembled is maintainable, disassemblable, and reassemblable.