UNINTERRUPTIBLE POWER SUPPLY DEVICE

An electromagnetic contactor () is connected between an AC power supply () and a load (), and is turned on during bypass power feeding. A control device () turns on a switch () and turns off the electromagnetic contactor () when an inverter () has a failure during inverter power feeding. The electromagnetic contactor () is turned on when a contact is closed by excitation of a coil according to a control signal from the control device (). The electromagnetic contactor () has a manual switch that can close the contact by being pressed from outside. An uninterruptible power supply device () includes a pressing force applying mechanism () that applies a pressing force to the manual switch, and a control circuit () that operates the pressing force applying mechanism when there occurs a failure that the electromagnetic contactor () cannot be turned on regardless of the control signal from the control device ().