Patent attributes
A refill for a writing tool includes an ink containing tube that is made from a resin material and formed in a straight cylindrical shape, and a writing tip that is attached to an end of the ink containing tube. A press-fit portion, formed at the end of the ink containing tube, has a thickness being made thickened toward an inner circumferential surface and has an opening hole penetrating in an axial direction at a central portion of the press-fit portion. The writing tip or a relay member supporting the writing tip is press-fitted and attached to the press-fit portion. The refill for a writing tool can ensure a necessary and sufficient amount of ink stored without expanding an outer diameter of the ink containing tube, and sufficiently secure mechanical strength of an end portion, and a writing tool using the same can be provided.