A pneumatic immersion lubricant pump, including a primary piston sliding in a sealed manner in contrast to at least one spring inside a cylindrical body together with which the primary piston defines a chamber provided on an opposite side of the primary piston with respect to that where the at least one spring is positioned, a body of the pump including at least one channel in which an element projecting from the primary piston is slidably housed in a sealed manner. The body of the pump including a plurality of cylinders each equipped with a loading port open on the outside of the pump body. Each cylinder housing a secondary piston axially constrained to the primary piston. The projecting element and the channel defining a pressurization duct of the chamber.