Embodiments of the present invention disclose a plug-in mechanism, a subrack including the plug-in mechanism, and a finished board, and relate to a power mechanism, so as to implement fast and reliable plug-in and plug-out by using a lever assistance effect, and a gearing effect of a parallelogram mechanism. The plug-in mechanism provided by an embodiment of the present invention is configured to be disposed between a sub-carrier frame and a parent carrier frame to implement plug-in and plug-out of the sub-carrier frame in the parent carrier frame, and the plug-in mechanism includes a driving part and a gearing part.