A construction machine comprising: a first hydraulic actuator; a second hydraulic actuator; a work implement driven by the first hydraulic actuator and the second hydraulic actuator; a first hydraulic pump; a second hydraulic pump; a first directional control valve provided in a first pump line that is a delivery hydraulic line of the first hydraulic pump and controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; a first speed-up directional control valve provided in a second pump line that is a delivery hydraulic line of the second hydraulic pump and controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; and a second directional control valve provided in the second pump line that is the delivery hydraulic line of the second hydraulic pump and controlling a flow rate and a direction of a hydraulic fluid supplied to the second hydraulic actuator, characterized in that: the construction machine includes: an excavation load sensor that detects an excavation load imposed on the work implement; and a first speed-up control section that drives the first speed-up directional control valve, and the first speed-up control section is configured to control a driving amount of the first speed-up directional control valve in response to the excavation load detected by the excavation load sensor, wherein the work implement includes a boom and an arm, the first hydraulic actuator is a boom cylinder that drives the boom, the second hydraulic actuator is an arm cylinder that drives the arm, the excavation load sensor is an arm cylinder bottom-chamber-side pressure sensor that measures a pressure of a bottom-side hydraulic chamber of the arm cylinder and a boom cylinder bottom-chamber-side pressure sensor that measures a pressure of a bottom-side hydraulic chamber of the boom cylinder, and the first speed-up control section is configured to control the driving amount of the first speed-up directional control valve on the basis of a deviation between the pressure of the bottom-side hydraulic chamber of the boom cylinder measured by the boom cylinder bottom-chamber-side pressure sensor and the pressure of the bottom-side hydraulic chamber of the arm cylinder measured by the arm cylinder bottom-chamber-side pressure sensor. a first hydraulic actuator; a second hydraulic actuator; a work implement driven by the first hydraulic actuator and the second hydraulic actuator; a first hydraulic pump; a second hydraulic pump; a first directional control valve provided in a first pump line that is a delivery hydraulic line of the first hydraulic pump and controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; a first speed-up directional control valve provided in a second pump line that is a delivery hydraulic line of the second hydraulic pump and controlling a flow rate and a direction of a hydraulic fluid supplied to the first hydraulic actuator; and a second directional control valve provided in the second pump line that is the delivery hydraulic line of the second hydraulic pump and controlling a flow rate and a direction of a hydraulic fluid supplied to the second hydraulic actuator, characterized in that: the construction machine includes: an excavation load sensor that detects an excavation load imposed on the work implement; and a first speed-up control section that drives the first speed-up directional control valve, and the first speed-up control section is configured to control a driving amount of the first speed-up directional control valve in response to the excavation load detected by the excavation load sensor, wherein the work implement includes a boom and an arm, the first hydraulic actuator is a boom cylinder that drives the boom, the second hydraulic actuator is an arm cylinder that drives the arm, the construction machine includes: an excavation load sensor that detects an excavation load imposed on the work implement; and a first speed-up control section that drives the first speed-up directional control valve, and an excavation load sensor that detects an excavation load imposed on the work implement; and a first speed-up control section that drives the first speed-up directional control valve, and the first speed-up control section is configured to control a driving amount of the first speed-up directional control valve in response to the excavation load detected by the excavation load sensor, wherein the work implement includes a boom and an arm, the first hydraulic actuator is a boom cylinder that drives the boom, the second hydraulic actuator is an arm cylinder that drives the arm, the excavation load sensor is an arm cylinder bottom-chamber-side pressure sensor that measures a pressure of a bottom-side hydraulic chamber of the arm cylinder and a boom cylinder bottom-chamber-side pressure sensor that measures a pressure of a bottom-side hydraulic chamber of the boom cylinder, and the first speed-up control section is configured to control the driving amount of the first speed-up directional control valve on the basis of a deviation between the pressure of the bottom-side hydraulic chamber of the boom cylinder measured by the boom cylinder bottom-chamber-side pressure sensor and the pressure of the bottom-side hydraulic chamber of the arm cylinder measured by the arm cylinder bottom-chamber-side pressure sensor.