To miniaturize a tube holding device, and to improve the safety of the work in the tube holding device to hold the tube and transmit the rotational force of a rotational drive source.

A tube holding device 1 is provided with a rotary shaft 2, a cam 2d which is provided on an outer circumference of the rotary shaft and has a slidable contact surface with the pressing-out effect in the radial direction of the rotary shaft, and a freely moving member 8 which is pressed out in the radial direction of the rotary shaft by the cam and transmits the rotational force. The freely moving member 8 is abutted on an inner circumferential wall surface of the tube (a steel tube 6) by the cam 2d, and the tube 6 is rotated together with the rotary shaft 2.