To provide a base isolation support device for a crane capable of preventing an influence of a horizontal-directional displacement in a structure side from being spread over a mast when a great vibration such as an earthquake is generated, while stabilizing support for the crane in a usual operation, and capable of avoiding the device from getting large to reduce a limitation in the aspect of a space.

The first trigger means 16 and the second trigger means 18 are provided to allow deformations of the first layered rubber 15 and the second layered rubber 17, by connecting a mast support member 14 to a structure 12 via the first layered rubber 15 capable of absorbing a Y-directional displacement, by connecting the mast 2 to the mast support member 14 via the first layered rubber 15 capable of absorbing an X-directional displacement, by supporting a load to restrict the deformations of the first layered rubber 15 and the second layered rubber 17, in the usual operation, and by allowing plastic deformations when a horizontal-directional acceleration acting on the structure 12 or the climbing crane 1 comes to a set value or more.