The utility model relates to an actuating device, in particular to a central manual device for a pneumatic linear actuator. The central manual device for the pneumatic linear actuator comprises an air cylinder, a piston, a piston rod, a valve rod, a manual operation mechanism, a switching mechanism for controlling connection of the manual operation mechanism with the valve rod, and a bracket, wherein the piston is arranged in the air cylinder, and fixedly connected with the piston rod; the piston rod is connected with the valve rod in a linkage manner; and the switching mechanism and the manual operation mechanism are fixedly arranged on the bracket. The central manual device for the pneumatic linear actuator adopts a novel integral design structure, overcomes the defects of prior disperse mounting, heavy structure and inflexible operation, the three traditional components, namely a supporting sleeve, a gear and a gear seat, are replaced with a bevel gear, so that the mounting dimension and precision of a relative position are ensured, the processing amount and turnover procedures of spare parts are reduced, the opening and closing of a valve are facilitated, the mounting, maintenance and debugging of the valve are facilitated, and the labor intensity and safety risk of an operator can be reduced.