Circular electric connector socket

The invention relates to a circular electric connector socket comprising a shell and a mounting flange. A positioning piece which is axially movable is arranged between the mounting flange and the shell, the shell and the positioning piece are assembled in a standstill locking manner, and standstill locking keys are arranged at the outer ends of the positioning piece. Standstill locking key groove matching with the standstill locking keys axially in an inserted manner to realize standstill locking of the mounting flange corresponding to the shell is reserved in the mounting flange. Radial mounting holes provided with a locking spring inside are arranged on the positioning piece, and a positioning ball presses against the inner side of the locking spring. A first positioning ball groove matching with the positioning ball fixedly to enable each standstill locking key to be fixed in the first positioning ball groove is arranged in the shell. A bearing unit is arranged on the positioning piece, and is used for mo