A portable sprayer for liquid or semiliquid products, including at least one Container (2) for a product to be dispensed which is associated with a pump assembly (100) which is actuated by an actuation means and is connected to a dispensing device. The pump assembly includes at least one screw piston (110), which interacts with the actuation means and is guided with a reciprocating combined rotary and translational motion in a hollow body (130) which is integral with the Container (2) and is provided with at least one intake port (137) and at least one delivery port (138).
