A working machine comprising: - an upperstructure; - a working equipment attached to the upperstructure; - a swing motor for rotating the upperstructure; - a drive unit for driving the swing motor; - a swing control device for outputting a target rotation speed for the swing motor, said target rotation speed corresponding to a control stroke of the swing control device; - an actual rotation speed sensor for sensing an actual rotation speed of the swing motor; and - a controller for controlling a drive torque of the drive unit such that a difference between the target rotation speed outputted from the swing control device and the actual rotation speed outputted from the actual rotation speed sensor is reduced to zero, characterized in that: the working machine further includes: - a work posture sensor for sensing a work posture of the working equipment; - a work load sensor for sensing the work load of the working equipment; and - a signal detector for detecting a signal value commensurate with a rotation speed of the swing motor, said rotation speed corresponding to a drive torque of the drive unit; the work posture sensor is further adapted to sense a working radius of the working equipment; the controller includes at least one of a first computing unit for computing a coefficient of a magnitude corresponding to the work posture sensed by the work posture sensor and a second computing unit for computing a coefficient of a magnitude corresponding to the work load sensed by the work load sensor, and further includes: - a correction-value computing unit for multiplying the signal value outputted from the signal detector and the coefficient outputted from the first computing unit or second computing unit to output a correction value for correcting the target rotation speed; and the first computing unit is adapted to calculate a large value as the coefficient when the working radius is small and to calculate a small value as the coefficient when the working radius is large. - an upperstructure; - a working equipment attached to the upperstructure; - a swing motor for rotating the upperstructure; - a drive unit for driving the swing motor; - a swing control device for outputting a target rotation speed for the swing motor, said target rotation speed corresponding to a control stroke of the swing control device; - an actual rotation speed sensor for sensing an actual rotation speed of the swing motor; and - a controller for controlling a drive torque of the drive unit such that a difference between the target rotation speed outputted from the swing control device and the actual rotation speed outputted from the actual rotation speed sensor is reduced to zero, - a work posture sensor for sensing a work posture of the working equipment; - a work load sensor for sensing the work load of the working equipment; and - a signal detector for detecting a signal value commensurate with a rotation speed of the swing motor, said rotation speed corresponding to a drive torque of the drive unit; - a correction-value computing unit for multiplying the signal value outputted from the signal detector and the coefficient outputted from the first computing unit or second computing unit to output a correction value for correcting the target rotation speed; and