An exemplary slide mechanism includes a main plate a slide plate, and two arched resilient members. The arched resilient members are disposed on the main plate. The slide plate is slidably laid over the main plate. A resisting member is fixed on one surface of the slide plate facing to the main plate. The resisting member keeps resisting the arched resilient members when the slide plate sliding along the main plate. A guiding surface is formed on the main plate. One end of each arched resilient member is fixed to the main plate, and the other end of each arched resilient member resists and is slidable on the guiding surface. A slide-type portable terminal device using the slide mechanism is also provided.