A high-voltage power supply device includes a circuit board having a piezoelectric transformer; a frequency-controlled oscillator for generating a frequency signal that drives the piezoelectric transformer in accordance with a control signal; a switching element connected to a primary side of the piezoelectric transformer for performing a switching operation in accordance with the frequency signal; a capacitor and inductor forming a parallel resonance circuit for performing a resonating operation owing to switching by the switching element; and a capacitance element connected across ground and the power-supply side of the inductor. The capacitance element and the inductor are arranged on the circuit board in such a manner that when the circuit board undergoes solder-mounting, the capacitance element and the inductor are immersed in a solder bath before the piezoelectric transformer.