A sliding mechanism and a slider electronic apparatus therewith are disclosed. The sliding mechanism is disposed in a casing of the slider electronic apparatus and includes a slide, a retaining wall, and a sliding member. The slide and the retaining wall are oppositely fixedly disposed. The sliding member is disposed to be slidable on the slide and keeps pushing the retaining wall. The retaining wall applies a reaction force on the sliding member to drive the sliding member to move on the slide. Another casing of the slider electronic apparatus is connected to the sliding member so as to be capable of moving together with the sliding member. Therein, a relatively shortest distance exists between the retaining wall and the slide. When the two casings are moved relatively, the casings can be kept moving automatically by the reaction force.