A fuel injection valve for an automotive internal combustion engine
comprises a needle valve and an opposite member which are in slidable
contact with each other in presence of fuel. A hard carbon thin film is
coated on at least one of the sliding sections of the base materials of
the needle valve and the opposite member. The hard carbon thin film has a
surface hardness ranging from 1500 to 4500 kg/mm.sup.2 in Knoop hardness,
a film thickness ranging from 0.3 to 2.0 .mu.m, and a surface roughness
(Ry) (.mu.m) which satisfies a relationship represented by the following
formula (A): Ry<(0.75-Hk/8000).times.h+0.0875 (A)where h is the
thickness (.mu.m) of the hard carbon thin film; Hk is the surface
hardness in Knoop hardness (kg/mm.sup.2) of the hard carbon thin film.