To provide a nut rotating device of favorable workability in which a nut can be easily and speedily moved for a long distance in moving the nut to a specified position of a long male screw.

A nut rotating device comprises a support frame 1, a passive rotation member 3 rotatably installed on the support frame 1, provided with a through hole 3d to penetrate a male screw 5 at an axial center position of a rotation axis, and provided with holding parts 3a, 3b to hold the nut 4 to be threaded with the male screw 5 at one end of the through hole 3d, a drive rotation member 7 rotatably installed on the support frame 1 to be apart from the passive rotation member 3, and rotation torque transmission means 3c, 7c, 12 to transmit rotation torque of the drive rotation member 7 to the passive rotation member 3.