The invention relates to an injection device (1), designed in particular for injecting fluid into an exhaust tract of an internal combustion engine, having a valve needle (14), an injection chamber (12) having at least one injection opening (44), and a control chamber (20). The injection device (1) is designed such that a pressure differential between the injection chamber (12) and the control chamber (20) brings about a displacement of the valve needle (14) between an open position in which a fluid flow through the injection opening (44) from the injection chamber (12) is released, and a closed position, in which the injection opening (44) is closed off. The injection chamber (22) and the control chamber (20) are hydraulically connected to an inlet (40, 42; 9), such that a pressure rise in the inlet (40, 42; 9) results in a pressure rise in the injection chamber (12), and a pressure rise in the control chamber (20) delayed in time relative to the pressure rise in the injection chamber (12), and said pressure differential brings about a displacement of the valve needle (14) from the closed position into an open position.