A connecting unit for connecting an electronic unit to a housing includes a first connecting component having a fastening hole, a second connecting component including a head and a stem, and a resilient buffering member sleeved on the first connecting component, and having an end that abuts against a board of the electronic unit and that has a mounting hole. A portion of the buffering member is between the first connecting component and the board. The stem extends through the board and the mounting hole to engage the fastening hole, such that the board abuts against the buffering member, and is spaced apart from the first connecting component and the head so as to be movably restricted relative to the housing between the head and the buffering member.