Abstract: A primary object of the present invention is to provide an improved joint structure for a window dummy to ensure that any joints can be easily rotated, turned or bent within a remarkably wide angle, and which shows good appearance. This joint structure comprises a hollow member including two half members each of which is formed with at least one of slidably engaging section capable of slidably engaging each other; and at least two connection members whose one end is fixed to a rod of arm, leg, or the like and the other end is rotatably connected to the other connection member in the hollow member. Further each of the connection member is independently fixed to the half member of the hollow member. One of the connection member is formed with means to prevent from interfering with the other half member fixed with the other connection member.