A fixing device for an injection nozzle, in particular, for an injection nozzle of an internal combustion engine with direct fuel injection. The injection nozzle includes a nozzle holder body whose cylindrical first and second end pieces interact with a first and a second bore hole of components of the internal combustion engine. For easy mounting and leakproof fastening of the injection nozzle, a clamping device acts upon the nozzle holder body. The clamping device holds in place, with a defined prestress, the first end piece in the first bore hole of a cylinder head. The second end piece preferably works together with the second bore hole of an intake arrangement, with the help of a reduction sleeve.