Abstract: A manually operated dispensing apparatus for dispensing pasty substances, in particular silicone, includes a hollow vessel, an air chamber formed by an elastically deformable wall, a double check valve placing the air chamber in communication with the interior of the vessel, a sealing element through which the paste to be dispensed is introduced, a front paste dispensing spout, a manually operated dispensing actuation lever, and a plunger located inside the hollow vessel. The dispensing actuation lever has two segments disposed at an angle with respect to each other. The elastically deformable wall is pressed by actuating the lever so as to cause air in the air chamber to be injected under pressure into a cavity in the vessel delimited by the plunger.