A scroll compressor includes: a frame fixedly installed in the casing to support a rotary shaft of the driving motor and having a second suction opening at its one side and a second discharge opening at its other side; a fixed scroll fixedly installed at the frame and having a first suction opening at its edgemost and a first discharge opening at its central portion; an orbiting scroll forming a first compression chamber by being engaged with the fixed scroll; a self-rotation preventing member interposed between the frame and the orbiting scroll for preventing a self-rotation of the orbiting scroll; and a vane making a linear movement in a radial direction of the frame according to an orbiting movement of the orbiting scroll, and forming between the frame and the orbiting scroll a second compression chamber including a spaces where the second suction and discharge opening exists.