Abstract: In a fluid injection nozzle, a leading end portion of a needle is provided with a first conical surface, a second conical surface and a notch. A seat line between the first and second conical surfaces comes in contact with a seat surface. A gap between the first conical surface and the seat surface gradually narrowed as going downstream, and a gap between the second conical surface and the seat surface gradually widened as going downstream. The notch extends from an upstream end of the first conical surface to a side opposite from the second conical surface to face the seat surface.

Abstract: On an inner wall of a bag-shaped hole portion of a nozzle body, a cross angle between the bag-shaped hole portion and a needle hole or an oblique high-pressure fuel passage of the nozzle body is made obtuse, i.e. at 90 degrees or larger, through an electrochemical machining process with a suitably-shaped electrode or through after-processing with a boring tool having a predetermined shape. The center of the bag-shaped hole portion may be deviated toward the high-pressure fuel passage or the high-pressure fuel passage may be connected to a maximum diameter portion of the bag-shaped hole portion to provide the obtuse cross angle. Thus, excessive stress on the inner wall of the bag-shaped hole portion or a breakage of the nozzle body due to a crack can be inhibited.