Abstract: A telescopic bracket has a retracted state and an extended state. The telescopic bracket comprises a fixed assembly, a moving member, and a spring. The moving member is movably coupled to the fixed assembly to move along an axial direction of the fixed assembly, causing the telescopic bracket to switch between the retracted state and the extended state. The spring is disposed between the fixed assembly and the moving member to provide an elastic restoring force to the moving member, and the cross section of the spring could be a trapezoidal shape, a rectangular shape, a square shape, a parallelogram shape, or an unequal quadrilateral shape. An open-up device using the telescopic bracket is also provided.