FUEL INJECTION VALVE

Disclosed is a fuel injection valve in which a movable core and a fixed core are enclosed in a cylindrical body. The cylindrical body has an annular groove formed therein, on an outer circumferential side of a region in which the movable core and the fixed core are opposed to each other, to define a thin portion of small wall thickness. In a cross section taken along a center axis of the fuel injection valve, the thin portion has curved line sections on both end sides thereof in a direction along the center axis such that the curved line sections respectively connect a bottom of the annular groove to side edges of the annular groove by curved lines. The curved line sections are provided over a range of larger dimension, from the respective side edges in the direction along the center axis, than a depth dimension of the annular groove.