The present invention reveals an over-current protection apparatus comprising a first electrode plate, a second electrode plate, a third electrode plate, a conductive element and a high resistance material layer, where the high resistance material layer may contact the first electrode plate to form a conducting path, the conductive element is connected to the first electrode plate and the second electrode, the thermally expanded conductive element can cut off current, the high resistance material layer is connected to the third electrode plate and the second electrode plate, and the thermal expansion coefficient of the high resistance layer is less than that of the conductive element. By virtue of the thermal expansion of the conductive element due to an over-current, the first electrode plate is departed from the third electrode plate so as to enforce the current flows through the high resistance material layer for current reduction. In addition, the heat generated from the high resistance material layer can be transferred to the conductive element to keep the conductive element expanded to cut off current.