The description provides a surge voltage protector used in a power supply unit of a low voltage power network. The surge voltage protector is provided with a metal housing (2), two electrodes (3,4) which are oppositely arranged in the axial direction, an electric arc ignition chamber (5) and at least one resistance igniter(6) which are inside the housing (2) and between the two electrodes (3,4), and an auxiliary igniting mechanism of a voltage switch member (7), wherein the ingiter(6) is connected with the electric arc ignition chamber (5) and is electrically connected with the housing (2) in one side and is electrically connected with the second electrode (4) in the other side; the voltage switch member (7)is electrically connected with the first electrode (3) in one side and is electrically connected with the housing in the other side; and a spark space is formed between the two electrodes (3,4) so that electric arc presents in the electric arc ignition chamber (5) when the spark space is ignited between the two electrodes (3,4). According to the surge voltage protector, the risk of surge voltage protector being endangered due to surge voltage protector damage or overloading is reduced; the voltage switch member(7) is arranged between the first electrode (3) and the housing (2), and there is some distance between the voltage switch member(7) and the electrode arc ignition chamber(5).