A construction machine comprising: an articulated front work implement formed by vertically rotatably coupling a boom, an arm, and a work tool to one another, and vertically rotatably supported by a machine body of the construction machine; operation devices (1c, 1d) configured to output operation signals for respectively operating the boom, the arm, and the work tool of the front work implement; a posture information sensor configured to detect posture information of each of the boom, the arm, and the work tool; and an information processing device configured to perform information processing on a basis of the posture information detected by the posture information sensor, design surface information as information on a target shape of an excavation object, and the operation signals from the operation devices (1c, 1d); the information processing device including a work point position computing section configured to compute a relative position of a work point set on the work tool with respect to the machine body on a basis of the posture information, a target surface setting section configured to set a target surface as a target of excavation work on a basis of the design surface information, characterised in that the information processing device comprises a primary operation determining section configured to determine which of operations of the boom and the arm is a primary operation as a main operation when the work point is moved along the target surface, and a recommended operation computing section configured to compute a recommended operation amount and a recommended operation direction of a secondary operation as another operation different from the primary operation in the operations of the boom and the arm according to an operation amount and an operation direction of the primary operation, and display the recommended operation amount and the recommended operation direction of the secondary operation on an instructing device, when the excavation work is performed. an articulated front work implement formed by vertically rotatably coupling a boom, an arm, and a work tool to one another, and vertically rotatably supported by a machine body of the construction machine; operation devices (1c, 1d) configured to output operation signals for respectively operating the boom, the arm, and the work tool of the front work implement; a posture information sensor configured to detect posture information of each of the boom, the arm, and the work tool; and an information processing device configured to perform information processing on a basis of the posture information detected by the posture information sensor, design surface information as information on a target shape of an excavation object, and the operation signals from the operation devices (1c, 1d); the information processing device including a work point position computing section configured to compute a relative position of a work point set on the work tool with respect to the machine body on a basis of the posture information, a target surface setting section configured to set a target surface as a target of excavation work on a basis of the design surface information, a work point position computing section configured to compute a relative position of a work point set on the work tool with respect to the machine body on a basis of the posture information, a target surface setting section configured to set a target surface as a target of excavation work on a basis of the design surface information, characterised in that the information processing device comprises a primary operation determining section configured to determine which of operations of the boom and the arm is a primary operation as a main operation when the work point is moved along the target surface, and a recommended operation computing section configured to compute a recommended operation amount and a recommended operation direction of a secondary operation as another operation different from the primary operation in the operations of the boom and the arm according to an operation amount and an operation direction of the primary operation, and display the recommended operation amount and the recommended operation direction of the secondary operation on an instructing device, when the excavation work is performed. a primary operation determining section configured to determine which of operations of the boom and the arm is a primary operation as a main operation when the work point is moved along the target surface, and a recommended operation computing section configured to compute a recommended operation amount and a recommended operation direction of a secondary operation as another operation different from the primary operation in the operations of the boom and the arm according to an operation amount and an operation direction of the primary operation, and display the recommended operation amount and the recommended operation direction of the secondary operation on an instructing device, when the excavation work is performed.