Captain Joe Roberts scored twice as the Scottish forwards dominated, with five of their seven tries coming from the pack. Ollie Blyth-Lafferty, Roberts and Nairn Moncrieff helped Scotland into a 12-point half-time lead before Hamish MacArthur stretched the advantage after the break.
Argentina briefly threatened a comeback, but Roberts' second try, followed by scores from Jamie Stewart and Harvey Preston, sealed a convincing victory.