Abstract: A bi-directional feeding gripper device including a single cylinder and upper and lower cylindrical cap members mounted to upper and lower ends of the cylinder and provided with pneumatic pressure passages communicated with the interior of the cylinder, respectively. An upper lifting piston having a driving rod and a lower gripping piston spaced from the lifting piston are disposed in the cylinder. A compression coil spring is disposed around the driving rod between the lifting piston and the gripping piston. The driving rod extends through the gripping piston such that its lower end is protruded beyond the lower end of the lower cap member. The gripper device also includes a gripper fixed to the lower end of the gripping piston to move vertically together with the gripping piston and provided with a pair of fingers each having one end pivotally mounted to the gripper and the other end pivotally mounted to the protruded lower end of the driving rod.