A construction machine is provided with: a rotating body (1d); an electric motor (16) for driving the rotating body; an operating device (4b) for outputting an operating signal according to an operating amount and operating direction; an inverter device (13) for controlling the electric motor on the basis of a control signal generated according to the operating signal; a position sensor (24) for detecting an actual speed of the electric motor; and a second controller (22) for determining whether at least one of a first condition and a second condition is satisfied, wherein the first condition is satisfied when a sign of a value obtained by subtracting an actual speed (V) from a target speed (V*) of the electric motor which is defined by the control signal is different from a sign of acceleration of the electric motor, and the second condition is satisfied when the difference between the target speed and the actual speed is greater than a reference value Vth and the acceleration is greater than a reference value ([beta]th). By virtue of this configuration, misjudgment and detection failure of an electronic control system can be prevented.