To provide a grooved pin having a simple configuration and a secure tightening holding force and inexpensive.

This grooved pin 1 is guided by a groove formed in parallel with an axial line and is pressed in along an inner face of a pressing-in hole 6. A return stop part 10 composed of a trough 11 recessed from a surface of a shaft part 2 and a crest 12 rising slightly at a peripheral fringe of the trough 11 is formed on the surface of the shaft part 2, a plurality of return stop parts 10 are provided at an equal interval in the circumferential direction on the surface of the shaft part 2, and the return stop part 10 is engaged in the pressing-in hole 6 when a force acts in the direction of pulling. The grooved pin does not singly rotate for a workpiece of course, and the grooved pin is not pulled out at all even if a force acts in the axial direction. Moreover, it is used in a section where vibration occurs to obtain sufficient reliability even if the workpiece is connected with it. Furthermore, it can endure the use as an important machine element and can respond to trust sufficiently.