CONSTRUCTION MACHINE

Provided is a hydraulic excavator 1 including a starter motor 11 for starting an engine 2 with electric power supplied from a lead-acid battery 12, a second electric system 15 connected in parallel with a first electric system 14 to connect a lead-acid battery 12 and a 24V electrical equipment 16, a 48V battery 18 for supplying electric power to the second electric system 15, a relay 17 for disconnecting connection between the first electric system 14 and the second electric system 15, and a vehicle body controller 13 connected to the second electric system 15 to control the starter motor 11 and the relay 17 or the like. The vehicle body controller 13 estimates a remaining charge amount of the lead-acid battery 12 and disables driving of the starter motor 11 until an estimation result is higher than or equal to a threshold, and when the estimation result is higher than or equal to the threshold, disconnects the connection between the first electric system 14 and the second electric system 15 by using the relay 17.