Abstract: Disclosed is an electrical power supply for use, for example, for a flash fusing device in an electrophotographic recording apparatus, in which a DC high voltage is generated from a low voltage of an AC power supply so that the high voltage DC energy is momentarily consumed or discharged. The electrical power supply is configured in a manner so that, in order to make unnecessary a charging capacitor and a current limiting resistor for preventing rectifier elements from being damaged, at least some of the rectifier elements are constituted by rectifying control elements such as thyristors or transistors and a control signal is given to those rectifying control elements so as to make the rectifying control elements be in an isolated state. By use of such a configuration, the electrical power supply can be reduced in size as well as in power loss. The effect can be fully exhibited not only in a fusing apparatus employing the electrical power supply but in a recording apparatus employing such a fusing apparatus.