The present invention embodies a fuel injector that takes up limited space when installed on the cylinder head of an associated engine. According to the invention in a fuel injection nozzle of the kind specified the wider portion of the nozzle body is provided with a slot which extends from the step toward the nozzle holder, the portion of the nozzle holder adjecent the nozzle body being provided with a slot. A chip member located in the slot secures the collar to the nozzle holder to retain the nozzle body relative to the nozzle holder.