The spinning knob includes a shell, a rotation member, and a pushing member. The rotation member is rotatably disposed on the shell. The rotation member includes a threaded portion for screwing with a screw. The pushing member is arranged on the shell and tends to abut against the rotation member to have circumferential interference with the rotation member so that the shell and the rotation member may rotate simultaneously. When the rotation member is screwed to the screw sufficiently and an end of the rotation member abuts against an object, if the shell is further rotated, the rotation member obliquely abuts against the pushing member to make the pushing member trip away from the rotation member so that the pushing member has no circumferential interference with the rotation member and that the shell is rotatable with respect to the rotation member.