To provide a nut holding member and a bolt joint structure of a tubular member performed by using the nut holding member.

The nut holding member 5 is used while being received in a hollow part of the tubular member when the tubular member 3 and joint-counterpart members 2, 4 are jointed with bolts 9, 11 and nuts 6. The tubular member has bolt holes for bolt-joint to the joint-counterpart members. An outer peripheral surface of the nut holding member has a shape, which contacts with the inner surface of the tubular member from inside, is limited in movement to a direction perpendicular to a tube axis of the tubular member and includes a positioning means for aligning the positions of the nuts held by the nut holding member with the bolt holes of the tubular member in the longitudinal direction of the tubular member. On the outer peripheral surface of the nut holding member, nut fitting parts 51 in which the nuts are fitted in a whirl-stopped state are provided in the arrangement aligning with the bolt holes of the tubular member. The nut fitting parts are provided with locking parts for holding the fitted nuts so that they do not fall out.