The present invention relates to a resetable over-current protection device. The device is characterized in that: disconnected areas are maintained at end faces of formed cutting regions of the protection device, wherein one or two of the end faces of the formed cutting regions are partly formed with electrically conductive layers so as to increase the lifespan of the device and allows easy manufacturing of the device. The present invention also provides a method of manufacturing the resetable over-current protection device. The method is characterized in that a polymer-based sheet is divided into a plurality of components from which resetable over-current protection devices are subsequently manufactured into the resetable over-current protection devices to save the cost of material.