Loading and unloading device

The invention provides a mounting and dismounting device capable of automatically matching a nut connected with a pipeline with a joint of a gas cylinder at a specified torque. A mounting/dismounting device (1) for mounting/dismounting a nut to which a pipe is connected to a joint (103) of a gas cylinder (100), the mounting/dismounting device (1) comprising: a three-dimensional shape measurement unit (20) for detecting the position and direction of the nut; a socket (25) in which the pipe can be inserted through an opening (25a) of the socket itself and which can be attached to and detached from the nut; a rotation drive unit for rotating the socket about the first axis so that the torque of the socket about the first axis becomes a predetermined torque set in advance to fit the nut to the joint; an arm (15) having a support part (18) to which the socket is attached at a first end of the arm itself, and capable of adjusting the position and direction of the support part with respect to a second end of the arm