A fastening mechanism includes a mounting seat mounted on a frame body, disposed at a mounting hole in a frame body, and configured with an accommodating space therein. The mounting seat has a mounting wall formed with an opening for access into the accommodating space, and an outer surrounding wall connected to a periphery of the mounting wall. An engaging member extends movably in the accommodating space in the mounting seat, and is operable so as to move from a releasing position, where the engaging member disengages a fastening hole in a peripheral device, to an anchoring position, where the engaging member engages the fastening hole in the peripheral device such that the peripheral device is fastened to the frame body. The engaging member can be retained releasably in a selected one of the anchoring and releasing positions.