A device for limitation of the injection pressure of a medical instrument for introduction of a fluid, having a housing, with an entrance of the housing for introducing the fluid at an inlet pressure, with an outlet of the housing for introducing the fluid to the instrument, with a flow-through channel of the housing connecting the entrance and the outlet and with a plunger guided in the housing which is impinged on by the pressure of the fluid and through this pressure is movable against a resetting force. On the plunger a blocking element is arranged, which is located in the flow cross section of the flow-through channel, and that the blocking element releases the flow cross section, when the pressure of the fluid impinging on the plunger lies beneath a value preset by the resetting force, and blocks the flow cross section when the pressure of the fluid impinging on the plunger exceeds this preset value and moves the plunger against the resetting force.
