Construction machine

Disclosed is a construction machine including: an engine generating power; a pump generating hydraulic pressure by receiving power generated from the engine; a main control valve receiving signal oil from the pump; a key switch capable of turning on and off power of an electronic unit; an engine control unit that maintains operation of the engine for a predetermined time and then stops operation of the engine when the key switch is switched from an on-state, during which power of the electronic unit may be turned on, to an off-state; and a pilot cut-off valve for opening and closing the signal oil according to the state of the key switch, and an accident caused by the engine control unit may be prevented by the construction machine.