A power supply device (1A, 1B, 1C) comprising: an input unit to which AC power is input from an AC power supply; a first rectifying unit configured to convert the AC power passed through the input unit into DC power; a power-factor improving unit configured to improve a power factor of the DC power output from the first rectifying unit; a first power storage unit configured to store the DC power passed through the power-factor improving unit and configured to supply the stored DC power to a load side; characterised in that the power supply device further comprises: a second rectifying unit connected to a portion where the input unit is connected to the AC power supply, the second rectifying unit being configured to convert the AC power into the DC power; a second power storage unit configured to store the DC power passed through the second rectifying unit, the second power storage unit being connected to the power-factor improving unit in parallel to the first power storage unit; and a control unit configured to operate using the electric power stored in the second power storage unit and, when a short-circuit failure occurs in the power-factor improving unit, being configured to perform control for interrupting the input unit to interrupt a route that starts at the input unit, runs, from the input unit, via the second rectifying unit, the second power storage unit, the power-factor improving unit, and the first rectifying unit, and ends at the input unit. an input unit to which AC power is input from an AC power supply; a first rectifying unit configured to convert the AC power passed through the input unit into DC power; a power-factor improving unit configured to improve a power factor of the DC power output from the first rectifying unit; a first power storage unit configured to store the DC power passed through the power-factor improving unit and configured to supply the stored DC power to a load side; characterised in that the power supply device further comprises: a second rectifying unit connected to a portion where the input unit is connected to the AC power supply, the second rectifying unit being configured to convert the AC power into the DC power; a second power storage unit configured to store the DC power passed through the second rectifying unit, the second power storage unit being connected to the power-factor improving unit in parallel to the first power storage unit; and a control unit configured to operate using the electric power stored in the second power storage unit and, when a short-circuit failure occurs in the power-factor improving unit, being configured to perform control for interrupting the input unit to interrupt a route that starts at the input unit, runs, from the input unit, via the second rectifying unit, the second power storage unit, the power-factor improving unit, and the first rectifying unit, and ends at the input unit. a second rectifying unit connected to a portion where the input unit is connected to the AC power supply, the second rectifying unit being configured to convert the AC power into the DC power; a second power storage unit configured to store the DC power passed through the second rectifying unit, the second power storage unit being connected to the power-factor improving unit in parallel to the first power storage unit; and a control unit configured to operate using the electric power stored in the second power storage unit and, when a short-circuit failure occurs in the power-factor improving unit, being configured to perform control for interrupting the input unit to interrupt a route that starts at the input unit, runs, from the input unit, via the second rectifying unit, the second power storage unit, the power-factor improving unit, and the first rectifying unit, and ends at the input unit.