PURPOSE: To give excess length to a filament contained in a metallic tube easily, by passing the metallic tube containing a filament through the first feeding device and the second feeding device slower in feeding speed than the first device successively and contracting the metallic tube in the longitudinal direction.

CONSTITUTION: A filament-bearing metallic tube 3 is manufactured by containing a filament 2 in a mild metallic tube 1 such as Al or Cu along its longitudinal direction. This tube 3 is passed through the first feeding device 4 and the second feeding device 5 successively. The device 4 consists of a pair of upper and lower rolls 6 and a pair of left and right rolls 7 and is driven at a specified speed. The device 5 consists of a pair of upper and lower rolls 8 and a pair of left and right rolls 9 and is driven at a feeding speed slower than the device 4. Consequently, the tube body 1 is pressed between the device 4, 5 and contracted in its longitudinal direction, and excessive length is given relatively to the filament contained in the tube body 1. Thus, metallic tubes 3' containing filament having excessive length can be obtained continuously.