A PTC resistor according to the present invention comprises at least one PTC composition which comprises at least one resin and at least two conducti ve materials. The at least two conductive materials comprises at least two c onductive materials different from each other. The at least one PTC composit ion may comprise a first PTC composition which comprises a first resin and a t least one first conductive material and a second PTC composition which is compounded with the first PTC composition and comprises a second resin and a t least one second conductive material. The at least one first conductive ma terial is at least partially different from the at least one second conducti ve material. One of the first resin and the second resin may comprise a reac tant resin and a reactive resin which is cross-linked with the reactant resi n. The PTC resistor may comprise a flame retardant agent. The PTC resistor m ay comprise a liquid-resistant resin.
