CONSTRUCTION MACHINE

A construction machine includes: a swing structure (1d); an electric motor (16) that drives the swing structure; an operating device (4b) that outputs an operating signal according to an operating amount and an operating direction; an inverter device (13) that controls the electric motor based on a control signal generated based on the operating signal; a position sensor (24) that detects an actual speed of the electric motor; and a second controller (22) that determines whether at least one of a first condition and a second condition is satisfied. The first condition is satisfied when a sign of a value computed by subtracting the actual speed V from a target speed V* of the electric motor that defined by the control signal; and the second condition is satisfied when a difference between the target speed and the actual speed is greater than a reference value Vth, and when the acceleration is greater than a reference value ²th. This prevents erroneous determination and failure of detection relating to determination of faults in an electronic control system from occurring.