A separation prevention device for a pipe joint has disengagement prevention members and a press member. The disengagement prevention members are disposed at a plurality of locations in a circumferential direction of the pipe, on an inner peripheral surface of an engaging tool or of a receiving opening itself and which are formed with claws. The press member presses the disengagement prevention member radially inward of the pipe and which engages the claw with the outer peripheral surface of an inserting opening. The claw of the disengagement prevention member and the claw of the disengagement prevention member which is adjacent to the former disengagement prevention member in the circumferential direction of the pipe are arranged so as to overlap on each other in the axial direction of the pipe in a state where the claws are engaged with the outer peripheral surface of the inserting opening.