A pull-out pin adapted to couple first and second objects (21, 22) to each other, each of the first and second objects (21, 22) being formed with a pin hole (211, 221), said pull-out pin being adapted to be removably and tightly inserted through the pin hole of the first object and into the pin hole of the second object, said pull-out pin including a first end surface, and a second end surface spaced apart from said first end surface, characterized in that said pull-out pin further includes: an outer surrounding surface connected between said first and said second end surfaces (11, 12), surrounding a central axis, and having a recessed surface portion that defines a vent groove extending from said first end surface in a direction toward said second end surface, and a helical groove that extends helically about the central axis from said first end surface toward said second end surface, and that intersects said vent groove, said helical groove has a first groove opening formed at said first end surface, a second groove opening formed at said second end surface, and a plurality of shallow groove portions disposed between said first groove opening and said second groove opening and intersecting said vent groove, said helical groove has a maximum depth larger than a maximum depth of said vent groove, the maximum depth of said vent groove is 0.13±0.02 millimeters; the maximum depth of said helical groove is 0.5 millimeters; a width of said helical groove is 1.0 millimeter, said first end surface is adapted to be disposed in the pin hole of the first object; said second end surface is adapted to be disposed in the pin hole of the second object; said outer surrounding surface further has a connecting surface portion extending from said first end surface toward said second end surface, and connected to opposite lateral sides of said recessed surface portion, and a frustoconical surface portion disposed between said connecting surface portion and said second end surface, connected to said recessed surface portion, and gradually converging toward said second end surface, and said pull-out pin further includes an operating hole that extends from said first end surface along the central axis. an outer surrounding surface connected between said first and said second end surfaces (11, 12), surrounding a central axis, and having a recessed surface portion that defines a vent groove extending from said first end surface in a direction toward said second end surface, and a helical groove that extends helically about the central axis from said first end surface toward said second end surface, and that intersects said vent groove, said helical groove has a first groove opening formed at said first end surface, a second groove opening formed at said second end surface, and a plurality of shallow groove portions disposed between said first groove opening and said second groove opening and intersecting said vent groove, said helical groove has a maximum depth larger than a maximum depth of said vent groove, the maximum depth of said vent groove is 0.13±0.02 millimeters; the maximum depth of said helical groove is 0.5 millimeters; a width of said helical groove is 1.0 millimeter, said first end surface is adapted to be disposed in the pin hole of the first object; said second end surface is adapted to be disposed in the pin hole of the second object; said outer surrounding surface further has a connecting surface portion extending from said first end surface toward said second end surface, and connected to opposite lateral sides of said recessed surface portion, and a frustoconical surface portion disposed between said connecting surface portion and said second end surface, connected to said recessed surface portion, and gradually converging toward said second end surface, and a connecting surface portion extending from said first end surface toward said second end surface, and connected to opposite lateral sides of said recessed surface portion, and a frustoconical surface portion disposed between said connecting surface portion and said second end surface, connected to said recessed surface portion, and gradually converging toward said second end surface, and said pull-out pin further includes an operating hole that extends from said first end surface along the central axis.