In a fuel injector 10, a first injection hole 155a and a second injection hole 155b having reference inside diameters Dn1, Dn2 different from each other are formed as a plurality of injection holes 155. In such a configuration, an L/D value obtained by dividing the flow channel length Ln1 of the first injection hole 155a by the reference inside diameter Dn1 of the first injection hole 155a agrees to an L/D value obtained by dividing the flow channel length Ln2 of the second injection hole 155b by the reference inside diameter Dn2 of the second injection hole 155b.