A device (1) for moving and positioning a member in space has a mobile member (2), first and second members (3, 4) attached to a frame (32), and first and second carriages (5, 6) slidable along the members (3, 4). A first pair of arms (7, 8) are hinged to the first carriage and to the mobile member, forming a first four-bar linkage. A second pair of arms (10, 11) are hinged to the second carriage (6) and to the mobile member, forming a second four-bar linkage. A third pair of arms (14, 15) are hinged to a third member (13) and to the mobile member (2), forming a third four-bar linkage. A fourth member (17) which is hinged to the frame (3, 4, 19, 32) of the device (1) rotatably bears the third member (13), with a first actuator (18) provided for moving the fourth member (17).