A high voltage transformer is provided to fit a mounting panel in a fitting groove by forming the fitting groove on the outer surface of an E-type core unit or an I-type core unit constituting the high voltage transformer and forming the mounting panel equipped with a rail corresponding to the fitting groove. A high voltage transformer includes an E-type core unit(10) and an I-type core unit(20). A primary coil and a secondary coil having a turn ratio higher than the primary coil are installed in the E-type core unit. The I-type core unit is connected to a lower part of the E-type core unit by welding or die matching. A mounting panel equipped with a rail is formed on a panel of an electronic apparatus in which the high voltage transformer is installed. A fitting groove(24) is formed outside the E-type core unit or the I-type core unit in a lamination direction of an E-type core(12) or an I-type core(22). The E-type core unit or the I-type core unit is fixed to the panel of the electronic apparatus without a bracket or welding by inserting the fitting groove into the rail.
