A construction machine comprising: a hydraulic pump pumping up a hydraulic working fluid in a tank and delivering it; a hydraulic actuator driven by the hydraulic working fluid delivered from the hydraulic pump; a meter-out passage through which the hydraulic working fluid discharged from the hydraulic actuator flows; a meter-out control valve provided in the meter-out passage and controlling the hydraulic working fluid flow rate in the meter-out passage by varying an opening area; a load sensor (SE5, SE6, SE2) detecting a load acting on the hydraulic actuator; and an operation device operating the hydraulic actuator, characterized in that the construction machine further comprises: an operation amount sensor detecting an operation amount of the operation device, and a control device configured to alternatively select a normal operation mode in which the opening area of the meter-out control valve is controlled based on the load and the operation amount and a substitution operation mode in which the opening area of the meter-out control valve is controlled based on the operation amount, wherein the control device is configured to further increase a delivery flow rate of the hydraulic pump when the substitution operation mode is selected than when the normal operation mode is selected, and wherein, when the substitution operation mode is selected, the control device is configured to increase the delivery flow rate of the hydraulic pump the smaller the load, and to increase the delivery flow rate of the hydraulic pump the larger the operation amount. a hydraulic pump pumping up a hydraulic working fluid in a tank and delivering it; a hydraulic actuator driven by the hydraulic working fluid delivered from the hydraulic pump; a meter-out passage through which the hydraulic working fluid discharged from the hydraulic actuator flows; a meter-out control valve provided in the meter-out passage and controlling the hydraulic working fluid flow rate in the meter-out passage by varying an opening area; a load sensor (SE5, SE6, SE2) detecting a load acting on the hydraulic actuator; and an operation device operating the hydraulic actuator, characterized in that the construction machine further comprises: an operation amount sensor detecting an operation amount of the operation device, and a control device configured to alternatively select a normal operation mode in which the opening area of the meter-out control valve is controlled based on the load and the operation amount and a substitution operation mode in which the opening area of the meter-out control valve is controlled based on the operation amount, wherein the control device is configured to further increase a delivery flow rate of the hydraulic pump when the substitution operation mode is selected than when the normal operation mode is selected, and wherein, when the substitution operation mode is selected, the control device is configured to increase the delivery flow rate of the hydraulic pump the smaller the load, and to increase the delivery flow rate of the hydraulic pump the larger the operation amount. an operation amount sensor detecting an operation amount of the operation device, and a control device configured to alternatively select a normal operation mode in which the opening area of the meter-out control valve is controlled based on the load and the operation amount and a substitution operation mode in which the opening area of the meter-out control valve is controlled based on the operation amount, wherein the control device is configured to further increase a delivery flow rate of the hydraulic pump when the substitution operation mode is selected than when the normal operation mode is selected, and wherein, when the substitution operation mode is selected, the control device is configured to increase the delivery flow rate of the hydraulic pump the smaller the load, and to increase the delivery flow rate of the hydraulic pump the larger the operation amount.