Abstract: A housing body of a fuel injector has a multi-part design; it includes a base member and at least one calibrating sleeve. Air is supplied and metered in through the calibrating sleeve, while the base member is used for sealing and attachment purposes. A dimensionally accurate machining of calibrating sleeves can be carried out simply and cost-effectively. The structural design easily yields many different variants. The fuel injector is especially suited for fuel-injection systems of mixture-compressing internal combustion engines having externally supplied ignition.