FUEL INJECTION VALVE

To provide a fuel injection valve for actualizing high-dispersion and high-homogeneity spray.SOLUTION: At least one of a plurality of injection holes is a flat injection hole of which an outlet opening part 15 has a long axis Ha and a short axis Hb, and the flat injection hole further includes at least one "specific flat injection hole". In the specific flat injection hole 131, the long axis Ha is perpendicular to a plane Sh including an injection hole axis Ho connecting the center of the inlet opening part 14 and the center of an outlet opening part 15 and parallel to a valve stem Z, and plane parts 157, 158 opposed to each other across the long axis Ha exist on the inner wall. On the inner wall on the side along which fuel runs during injection with respect to the long axis Ha, the curvature radius of the long-axis-direction end of the inlet opening part 14 is set as a first curvature radius R1, and the curvature radius of the long-axis-direction end of the outlet opening part 15 is set as a second curvature radius R2. A curvature radius ratio as the ratio of the second curvature radius R2 to the first curvature radius R1 is within 40-100%.SELECTED DRAWING: Figure 8 【課題】高分散、高均質な噴霧を実現する燃料噴射弁を提供する。【解決手段】複数の噴孔のうち１つ以上は、出口開口部１５が長軸Ｈａおよび短軸Ｈｂを有する扁平噴孔であり、扁平噴孔はさらに１つ以上の「特定扁平噴孔」を含む。特定扁平噴孔１３１は、入口開口部１４の中心と出口開口部１５の中心とを結ぶ噴孔軸Ｈｏを含み弁軸Ｚに平行な平面Ｓｈに長軸Ｈａが直交し、内壁に、長軸Ｈａを挟んで対向する平面部１５７、１５８を有する。長軸Ｈａに対し噴射時に燃料が沿う側の内壁において、入口開口部１４の長軸方向端部の曲率半径を第１曲率半径Ｒ１、出口開口部１５の長軸方向端部の曲率半径を第２曲率半径Ｒ２とする。第１曲率半径Ｒ１に対する第２曲率半径Ｒ２の比である曲率半径比は４０％～１００％の範囲にある。【選択図】図８