A construction machine comprising: a hydraulic pump of variable displacement type; a regulator that regulates displacement volume of the hydraulic pump; a plurality of hydraulic actuators (3, 4) driven by a hydraulic fluid delivered from the hydraulic pump; a plurality of flow control valves (5, 6) that control supply and discharge of the hydraulic fluid to and from the plurality of hydraulic actuators (3, 4); a plurality of operation devices (7, 8) for operating the plurality of flow control valves (5, 6); an operation amount sensor (9, 10, 11, 12) that detects each of operation amounts of the plurality of operation devices (7, 8); and a controller that controls the regulator according to each of the operation amounts of the plurality of operation devices (7, 8) detected by the operation amount sensor (9, 10, 11, 12), wherein the controller is configured to compute a first target displacement volume for each of the operation amounts of the plurality of operation devices (7, 8), characterized in that the controller is configured to compute a second target displacement volume greater than the first target displacement volume for the same operation amount, for each of the operation amounts of the plurality of operation devices (7, 8), select as a final target displacement volume (Qfin) either smaller one of a sum total value of a plurality of first target displacement volumes (Qs1, Qs2,..., Qsn) computed for the operation amounts of the plurality of operation devices (7, 8) and a maximum value (Qcmax) of a plurality of second target displacement amounts (Qc1, Qc2,..., Qcn) computed for the operation amounts of the plurality of operation devices (7, 8), and control the regulator according to the final target displacement volume (Qfin). a hydraulic pump of variable displacement type; a regulator that regulates displacement volume of the hydraulic pump; a plurality of hydraulic actuators (3, 4) driven by a hydraulic fluid delivered from the hydraulic pump; a plurality of flow control valves (5, 6) that control supply and discharge of the hydraulic fluid to and from the plurality of hydraulic actuators (3, 4); a plurality of operation devices (7, 8) for operating the plurality of flow control valves (5, 6); an operation amount sensor (9, 10, 11, 12) that detects each of operation amounts of the plurality of operation devices (7, 8); and a controller that controls the regulator according to each of the operation amounts of the plurality of operation devices (7, 8) detected by the operation amount sensor (9, 10, 11, 12), wherein the controller is configured to compute a first target displacement volume for each of the operation amounts of the plurality of operation devices (7, 8), characterized in that the controller is configured to compute a second target displacement volume greater than the first target displacement volume for the same operation amount, for each of the operation amounts of the plurality of operation devices (7, 8), select as a final target displacement volume (Qfin) either smaller one of a sum total value of a plurality of first target displacement volumes (Qs1, Qs2,..., Qsn) computed for the operation amounts of the plurality of operation devices (7, 8) and a maximum value (Qcmax) of a plurality of second target displacement amounts (Qc1, Qc2,..., Qcn) computed for the operation amounts of the plurality of operation devices (7, 8), and control the regulator according to the final target displacement volume (Qfin).