Disclosed is a soft-start circuit for power-up, which includes a reference value generation circuit, a protection threshold generation circuit and a control circuit. The reference value generation circuit outputs a reference value, which increases slowly, during a start-up process for power-up. The protection threshold generation circuit outputs a protection threshold, which increases slowly, during the start-up process for power-up. The control circuit controls an output voltage to increase slowly along with the reference value based on the reference value, during the start-up process for power-up, and to limit an output current based on the protection threshold to limit the output voltage, during the start-up process for power-up. In this way, even if the output current must operate at the peak current, a smoother current output is realized, and operation at the maximum peak current for a long-time during start-up is not allowed.