To enable a mass production to be precisely conducted by improving durability and a strength without existing a brittle part to a moment and smoothly supplying an ink.

The trip for a writing instrument comprises a small diameter part 4 having an inner diameter corresponding to the outer diameter of a ball 12 rotatably assembled at its tip end, a large diameter part 8 having an inner diameter larger than that of the part 4, a coupling part 6 for flexibly coupling the part 4 to the part 8 and made of a curved surface, and a reinforcing part 7 formed to project to its outside between the part 6 and the part 8. In this case, a predetermined plate material is deep drawn at many stages to integrally form the trip for the instrument.