PURPOSE: To provide a suction cup type fixing device capable of easily sucking and releasing with a plane-shaped locked body in a locked condition.

CONSTITUTION: A locking pillar 2 protrudently formed in the back periphery of a suction cup 1 is passed through a main hole 41 of a plane-shaped locked body 4, and a projection 3 protrudently formed in the back periphery of the suction cup 1 is passed through an auxiliary hole 42 of the locked body 4. By pulling the tip of the projection 3 protruded from the auxiliary hole 42, the suction cup 1 can easily be released. The locking piller and the main hole 41 are omitted, and the locked body 4 comes into directly contact with the back center of the suction cup 1.