A temporary frame system includes four masts arranged outside of a building to be constructed. The frame system includes a climbing mechanism mounted on each mast for upward and downward movement thereon, a canopy frame fixed at four corners by respective climbing mechanisms and horizontally covering the entire upper surface of the building, a plurality of overhead traveling cranes arranged on the lower surface of the canopy frame, and a jib crane movable along a guide rail provided on an upper surface of the canopy frame. The overhead traveling crane includes a main rail positioned on a lower surface of the canopy frame and subsidiary rails arranged on both sides of the main rail in parallel thereto. A transporting girder is movably supported on the main rail and subsidiary girders are movably supported on the subsidiary rails. A plurality of hoists are provided on the overhead traveling crane. The transporting girder is a dual type which has two, first and second girders.