The utility model provides an use floater device in pit, which comprises an outer shell. Fix the inner shell in the shell, the intrastructure is having the blind end and the sleeve that opens wide theend, is equipped with the opening on the lateral wall of blind end in being close to of inner shell, locate the ball seat body in the inner shell, ball seat body structure is hollow sleeve to can slide between the primary importance of exposing the opening and the second place of closing the opening, install in the ball cover of the unlimited end of inner shell department, the ball cover structure all is equipped with the cylindrical cover of fretwork of through -hole for top and periphery to it is used for holding spheroidal accommodation space to have formed between the ball cover and the ball seat body, and arrange the stop device between inner shell and the ball seat body. In the time of can realizing that the well is gone into to tub cluster, be the single circulation state of annular space in to tub cluster between pipe cluster and floater device's annular space, after the pipe cluster target in place, managed string and floater device's annular space is not circulation state within a definite time to can keep this kind of state always.