To provide a mounting strut for a wall panel or the like with which assembling of the wall panel of an exhibition booth, assembling of a wall frame or a sample panel, demolition or replacement can be done by one-touch operation without using tools such as a hammer or a driver or the like, and which facilitates and quickens the work, and semi-permanently eliminating the maintenance of a strut or the supplement of a nail or the like.

In order to solve the problem, the mounting strut of the panel and its mounting device are so constituted that the wall panel, the window frame or the sample panel are mounted by a strut body, a lower supporting tool fixed to the strut body, an upper supporting tool mounted to the strut body in a liftable manner and/or an intermediate supporting tool.