A push button for a pressurised-product dispensing system, including an actuation body having an orifice for ejecting the product, a needle closing off the ejection orifice and a sleeve having a mounting well, the body being mounted to slide about the sleeve between high and low positions, forming between them a sealed space for conveying the product, the needle being associated with the sleeve by a link rotatably mounted on the sleeve to actuate the reversible movement of the needle between a closure position—or respectively an open position—of the ejection orifice when the body is in the high position—or respectively in the low position—, the needle provided with geometric means that interact with the body to exert a force holding the needle in a mounting position in which the needle projects from the body to enable the link to be associated with the needle.