To provide a stable power supply device preventing erroneous operation of a thyristor or the like by resonance caused between a coil and a capacitor constituting a noise filter and an induction constituent of a line against a steep change in voltage and current at the moment of conduction of the thyristor or the like when power supply voltage with a controlled phase controlled by the thyristor or the like is impressed.

This power supply device uses alternating voltage, which has a controlled phase controlled by the thyristor or the like, and has the noise filter constructed of the coil and the capacitor and installed behind a full-wave rectifier rectifying the power supply into direct current.