A handgun, particularly an automatic pistol, with a grip piece, a breech that can be longitudinally displaced relative to the grip piece, and a breechblock mechanism that can be actuated on both sides and serves for holding the breech in its open position. The breechblock mechanism has a breechblock lever that is realized in the form of a one-piece punched and bent part and has two lateral parts that are integrally connected to one another by a crosspiece, as well as operating parts that are integrally connected to the respective lateral parts.