PURPOSE: To let a pneumatic splicer provide god seam by applying air streams swirling in two different directions to a double thread attracted in a nozzle pipe and thereby carrying out untwining of thread ends with good performance through untwining of the double thread's upper and lower twist one after the other.

CONSTITUTION: When a thread is cut occasionally, first a suction pipe 1 revolves to attract fast the thread YB on the bobbin side while another suction pipe 2 attracts fast the thread YP on the package side. These threads are sent into front of a pneumatic splicing device 3. When thereafter thread cutting devices 14, 15 cut both threads, a nozzle pipe 26 is put in operation to suck cut-off thread ends through respective nozzle holes 12, 13. At this time, in the nozzle pipe 26, compressed air first jets out of a jet hole 27 to untwine the upper twist of the double thread YB and then another jet is given from a jet hole 28 to untwine the lower twist. When untwining of thread ends is completed, the threads are drawn into a splicing hole 5 in line, and now splicing is carried out by a swirling stream of compressed air jetting out of an air leading hole.