The present invention provides a method for manufacturing metal nanoparticles, comprising: dissociating at least one metal precursor selected from the group consisting of silver, gold and palladium; reducing the dissociated metal precursor; and isolating the capped metal nanoparticles with an alkyl amine. The present invention provides a method for manufacturing metal nanoparticles which can be performed with simpler equipment compared to the gas phase method, can provide metal nanoparticles in high yield by only using alkyl amine without using any surfactant in high concentration which further allows mass production, and can provide metal nanoparticles having high dispersion stability and uniform size of 1-40 nm.