PURPOSE: To attach a suction cup to a rough surface tightly and easily and without an apprehension of the falling-off, by interposing an inelastic sealing material between the suction cup and the rough surface.

CONSTITUTION: When it is desired that the suction cup 1 is attached to a relatively rough surface 3 such as a wood surface, a concrete wall surface and the like, it is attached to the surface 3 by interposing an inelastic sealing material 2 therebetween. As the inelastic sealing material 2 it is preferred to use putty for glass, oily cauking material, polybutenes, butyl rubber, asphalt containg rubber, or the like. Thus, when the suction cup 1 is pressed against the surface, the sealing material 2 is deformed in conformity with the rough surface 3, and as the sealing material 2 is remainded deformed because of its inelasticity, the suction cup 1 is attached airtightly and securely.