Milking robot device for automatically milking a dairy animal, comprising a milking box having milking cups and a robot arm having an end effector for applying the milking cups to the teats of the dairy animal, on which milking box the robot arm is suspended above the dairy animal to be milked. The robot arm comprises a first arm part connected to the milking box by a first joint, and a second arm part connected to the first arm part by a second joint and provided with an end effector. The first and second arm part, respectively, is pivotable in a vertical plane with respect to the milking box and the first arm part, respectively, by a first and second actuator, respectively. The end effector is movable within an operating range by the robot arm. The milking robot comprises a weight compensation device having a spring device between the milking box and the robot arm. This is configured to exert a first torque about the first joint and a second torque about the second joint, in such a way that, viewed over the operating range, the first torque compensates for the torque exerted by gravity on the arm about the first joint by at least half, in particular by at least 90%, and the second torque compensates for the torque exerted by gravity on the arm about the second joint by at least half, in particular by at least 90%. Consequently, a compact robot arm is provided, the joints which are suspended relatively high up can be protected from dirt in an efficient manner, and they can be operated using much lighter actuators, so that a great deal of energy can also be saved.