A self-sealing flexible seal includes a seal component A and a seal component B, each being hollow ball-like. In the portion of two pole parts of the each seal component, there is one annular opening per pole. The form of two seal components is similar figures, and two seal components are formed from a flexible material. The seal component A is arranged on the outside of the seal component B. The seal component A and the seal component B are arranged by a two-sheet pile, and are arranged in the state where it moreover contacted. Each of the seal component A and the seal component B possesses the slits of N pieces which have similar figures, the form of each slit is the form prolonged from the near side of the annular opening to the near side of another annular opening.
