Sir Sean Connery - the then-Bond - was pictured with the gun for publicity photos for the 1963 movie From Russia With Love, the second big-screen Bond adventure.
Images of the Scottish actor holding the Walther LP MOD.53 were used in posters and the film's ad campaign, and have become iconic for film fans.
The last time the pistol appeared at auction was at a Christie's James Bond sale in 2001, where it was sold for 14,100. The gun - actually an air pistol, rather than secret agent's tool - sold for almost 14 times the highest estimate given by experts.
It sold for 277,250 at the memorabilia sale at Christie's in London yesterday, despite being expected to fetch just 20,000.
The new owner of the gun wished to remain anonymous.