An instrument for robotic surgery that can be mounted at the distal end (2) of an operative arm (3) of an apparatus for robotic surgery, which instrument (1) comprises an effector device (27) for performing a given action on the body of a patient during a surgical operation, an articulation assembly (4) for supporting the effector member (27) and connecting it to the distal end (2) of the operative arm (3), a transmission assembly (6) connected to the articulation assembly (4) for moving and actuating the effector device (27), and sensors (28) mounted on the articulation assembly (4) for detecting the forces and torques applied to the effector device (27). The articulation assembly (4) has a cross-shaped supporting and movement member (18 180) articulated to the distal end (2) of the operative arm (3) for supporting the effector device (27) in a mobile way.
