PURPOSE: To provide a spigot protruding part forming piece allowing a protruding part to be formed at the spigot side part of a pipe without taking time.

CONSTITUTION: A spigot protruding part forming piece 10 is disposed in such a way as to lie across a groove part 5 formed on the outer peripheral surface of a spigot side part 4 in a pipe and the tip face 4a of the spigot side part 4. An engaging protruding part 11 engaged being fitted into the groove part 5 is formed at the spigot protruding part forming piece 10, and a stud bolt 13 is embedded in a bolt hole 12 extended along the axial direction of the pipe on the spigot tip side. When the tip of the stud bolt 13 is pressed to the tip face 4a of the spigot side part 4, the spigot protruding part forming piece 10 moves in an (a) direction, and the engaging protruding part 11 of the spigot protruding part forming piece 10 is engaged with the spigot tip side face 5a of the groove part 5 so as to fix the spigot protruding part forming piece 10 to the spigot side part 4.