Container gripper comprising a main frame (2) and movable supporting members (7) for gripper fingers (8-9) movable between an open position and a closed position. The container gripper is provided with a finger displacement detecting sensor (20, 21) which is responsive to the instantaneous position of the gripper fingers (8, 9). The finger detecting sensor may consist of a Hall effect assembly (20) formed by a magnet (10) and a Hall effect sensor (4) or of an optical encoder (21).