To solve defects in a single-sided suction cup whose application was limited to pressure-fitting to one side and in a conventional double-sided suction cup which became too thick because of the need for a connection part of both suction cups.

This double-sided suction cup is characterized by its shape with a hole bored in a perpendicular direction of two suction cup surfaces placed back to back, wherein a center part for connecting suction cups at both faces is eliminated and formed into a cavity 1-2. This double-sided suction cup can pressure-fit two smooth surfaces when inserted between the two surfaces and can be made very thin when pressure-fitting them.