To provide a construction machine capable of facilitating the operation of a drain valve attached to a fuel tank and improving the workability of maintenance.

The construction machine includes: a machine chamber 7 provided in a turning body 3; a fuel tank 10 provided adjacently to the machine chamber 7 at the front of the machine chamber 7; a hydraulic oil tank 9 provided adjacently to the fuel tank 10 inside the machine chamber 7; and a maintenance door 11 provided so as to be opened and closed on the right side part of the machine chamber 7 and forming the right side face part of the turning body 3 together with the right side face part of the fuel tank 10. The hydraulic oil tank 9 is provided facing the maintenance door 11, and the fuel tank 10 is provided with a drain discharge pipe 20 for discharging water accumulated at the bottom part to the outside and a drain valve 21 for opening and closing the drain discharge pipe 20. In the construction machine, the drain valve is provided between the maintenance door 11 and the hydraulic oil tank 9.