To provide an uninterruptible power supply unit with high reliability of power feeding to a load.

The uninterruptible power supply unit comprises: a plurality of uninterruptible power supply modules U1-U3 connected in parallel between an AC power supply 1 and a load 2; a plurality of bypass modules B1, B2; and a bypass switch BS. The respective bypass modules B comprises: a thyristor 10 connected between the AC power supply 1 and the load 2; and a control section 11 that turns off the bypass switch BS in an inverter feeding mode and turns on the thyristor 10 and the bypass switch BS when the uninterruptible power supply module U is damaged in an inverter feeding mode. Thus, bypass feeding can be performed even when one bypass module B is damaged.