To provide a connecting structure for a rolling stock air conditioning duct capable of saving time and trouble for connecting, and improving the airtightness of a connecting part between the air conditioning ducts by a simple structure.

End part opening portions 1c of the air conditioning ducts 1 forming heat insulating boards 1A, 1B to have square cross sections are faced with each other, and a band-shaped joint tape 2 for joining the air conditioning ends is wound around the whole circumference of end outer peripheral surfaces a of both facing air conditioning ducts 1, 1. A connecting frame 3 that is shorter than the whole circumference of the outer peripheral surfaces of the air conditioning ducts 1 and stiffer than the air conditioning duct 1 is bonded to a winding part of the joint tape 2, and the air conditioning ducts are wound by an exterior tape 5 while covering the connecting frame 3 and the joint tape 2.