To provide a new method for attaching a hair material for increasing hair in which the hair material for increasing hair can simply be attached in a short time without requiring skill to a worker and elimination of the hair material for increasing hair can effectively be prevented even when hair is washed.

The method for attaching the hair material for increasing the hair comprises a own hair-inserting step for inserting one's own hairs 3 from one end side of the tube 1 into a tube 1 mainly composed of a rubber or a resin, a hair material-inserting step for inserting the hair material for increasing the hair from the other end side of the tube 1 into the tube 1 and a heating step for contracting the tube 1 by heating the tube 1 after carrying out the own hair-inserting step and the hair material-inserting step.