The present invention relates to an apparatus for opening and closing a cover of a cellular phone in which a slide module capable of slidably opening and closing a cover of a cellular phone is constructed in a structure of using an elastic force of a spring, so that it is possible to precisely recognize an opening and closing operation of a cover, and an opening and closing operation of a cover is efficiently achieved. The apparatus includes a body having a keypad, a cover being engaged to the body slidably in forward and backward directions and having a display panel, an upper plate engaged to a lower side of the cover, a lower plate engaged to an upper side of the body, wherein the upper plate is slidably engaged to the lower plate, a rotation plate rotatably engaged between the upper and lower plates and adapted to slidably move the upper plate in forward and backward directions with respect to the lower plate, an elastic support unit having one end fixed to the rotation plate and the other end movably supported by an upper surface of the lower plate, wherein the elastic support unit is adapted to elastically support the rotation plate when the upper plate is slidably moved, and a stopper unit provided in the upper and lower plates and adapted to limit a slidable movement of the upper plate with respect to the lower plate.