PROBLEM TO BE SOLVED: To provide a device for melting and welding of a tube, which enables registering of the positions for the end of a tube with the position of a wing part of a wafer to be facilitated, without upgrading the dimensional precision of each part so much as unnecessarily and besides managing strictly the assembly of each part.SOLUTION: This device for melting and welding of the tube includes a carriage 14 which carries a body block 40 receiving a transmitted drive force, and a wafer retaining member 41 which retains the wafer 13 in such a way that the wafer 13 assumes a position where the wafer 13 extends crossing over the center line of the tubes 100 and 102. In addition, the carriage 14 includes a leaf spring 42 which supports the wafer retaining member 41 in a floating state, that is, in a vertically displaceable manner to the body block 40. Besides, below the wafer retaining member 41 of the device body, a height adjustment mechanism 55 for adjusting the height of the wafer retaining member 41 is provided.
