The present application discloses a TNPC inverter device, comprising: a TNPC inverter module and a short circuit detecting module. The TNPC module at least comprises an inverting bridge arm and a bi-directional switching bridge arm. The inverting bridge arm comprises at least two switches connected in series; the bi-directional switching bridge arm comprises at least two switches. The short circuit detecting module mainly consists of two switch detecting unit corresponding to the two switches in the inverting bridge arm respectively. Increasing the voltage drop of the switches in the inverting bridge when a short circuit occurs in the TNPC module by some way, then it could realize the short circuit detecting module is able to detect all the paths of the short circuit in the TNPC module to simplify the peripheral circuit of the TNPC module in the TNPC inverter device.