The invention relates to a flow restrictor (1) for restricting a volume flow through a liquid line, said flow restrictor comprising a support (10) having a passage and a bent flat spring (11) attached to the support (10). The flat spring (11) comprises at least one spring tab (12) and the passage at least one opening (13), the spring tab (12) and the opening (13) having a substantially identical extension along a longitudinal direction. The spring tab (12) is designed and arranged above the opening (13) in such a manner that it increasingly rests against the support (10) with increasing differential pressure, thereby gradually making the opening (13) smaller and continuously reducing the passage within a defined pressure range. The dimensions of the opening (13) are adjusted corresponding to the size of the spring tab (12), thereby allowing a compact flow restrictor (1) which is less susceptible to dirt. The continuous reduction of the passage allows an increase in vibration resistance of the flow restrictor (1).