To solve problem of a conventional socket with integrated two or more types of sockets of different diameters wherein idle rotation occurs or the overhead work with three or more-type multi-stage socket is disabled when an auxiliary socket is used.

The idle rotation produced by the reverse movement of the auxiliary socket is prevented from occurring and the overhead work with three or more-type socket is enabled by forming the lockable and unlockable stopper of the auxiliary socket. Specifically, the multi-stage socket with a stopper device for temporarily fixing the auxiliary socket which is instantaneously displaced by a spring is desirably used.