a torque control device controlling torque of first and second mechanical units connected coaxially to each other through connecting members includes a controller generating first and second references from a command from a host system , first and second motors respectively driving the first and second mechanical units , first and second motor control units respectively controlling the first and second motors on the basis of the first and second references . the first and second references synchronously accelerate the first and second motors to first rotational speed , then increase rotational speed of the second motor according to a speed profile to produce torsional torque in the connecting members , decelerate the second motor to the first rotational speed after the torsional torque reaches a predetermined value , and synchronously decelerate and stop the first and second motors after a predetermined time period elapses .