A work machine comprising: a machine body; a work arm that has, on one end side of the work arm, a work device that performs loading of a work target object onto a haulage machine, and is, on another end side of the work arm, attached to the machine body; a posture sensor (24, 25, 26, 27, 28) that senses a posture of the work arm including the work device; a load sensor (29, 30, 31, 32) that senses a load acting on the work arm; a notification device for giving notification of a work instruction to the haulage machine; and a controller that determines, on a basis of the posture and the load, that a haulage step of hauling the work target object onto the haulage machine has been performed by the work arm, measures a weight of the work target object during the haulage step, and determines, on the basis of the posture or the load, that a loading step of performing loading of the work target object onto the haulage machine has been performed by the work arm, characterized in that the controller is configured to sense the work instruction via the notification device, determine a start of loading work for the haulage machine and an end of the loading work on a basis of an operation state of the work machine at a time of the sensing of the work instruction, integrate the weight of the work target object that has been measured from the start of the loading work until the end of the loading work, and calculate a loaded amount of the haulage machine, and output the loaded amount to an external terminal at the end of the loading work. a machine body; a work arm that has, on one end side of the work arm, a work device that performs loading of a work target object onto a haulage machine, and is, on another end side of the work arm, attached to the machine body; a posture sensor (24, 25, 26, 27, 28) that senses a posture of the work arm including the work device; a load sensor (29, 30, 31, 32) that senses a load acting on the work arm; a notification device for giving notification of a work instruction to the haulage machine; and a controller that determines, on a basis of the posture and the load, that a haulage step of hauling the work target object onto the haulage machine has been performed by the work arm, measures a weight of the work target object during the haulage step, and determines, on the basis of the posture or the load, that a loading step of performing loading of the work target object onto the haulage machine has been performed by the work arm, characterized in that the controller is configured to sense the work instruction via the notification device, determine a start of loading work for the haulage machine and an end of the loading work on a basis of an operation state of the work machine at a time of the sensing of the work instruction, integrate the weight of the work target object that has been measured from the start of the loading work until the end of the loading work, and calculate a loaded amount of the haulage machine, and output the loaded amount to an external terminal at the end of the loading work. sense the work instruction via the notification device, determine a start of loading work for the haulage machine and an end of the loading work on a basis of an operation state of the work machine at a time of the sensing of the work instruction, integrate the weight of the work target object that has been measured from the start of the loading work until the end of the loading work, and calculate a loaded amount of the haulage machine, and output the loaded amount to an external terminal at the end of the loading work.