CONSTRUCTION MACHINE

To provide a technique where a case of shutting off a battery shutoff switch while a key switch is on is detected, and a warning according to a risk can be issued at time of restart.A construction machine includes: the key switch, an engine start switch, an engine stop switch, a notification device, a controller, and the battery shutoff switch. The controller chronologically stores operation histories of the key switch, engine start switch, and engine stop switch in a history storage section in a non-volatile manner. The controller determines, on the basis of the stored operation history, a risk content in a case of shutting off the battery shutoff switch while the key switch is on. In a case where, the controller is restarted by resuming the battery shutoff switch and turning on the key switch, the controller controls the notification device so that the notification device issues a warning according to the risk content, on the basis of a result of the determination.