The present invention relates to an internal bone plate fixation device (1) for use as a means of synthesis in anatomical regions or epiphysis/metaphysis with poor coating of soft tissues, of the type comprising a bone plate (2) that is bilobate or having eight-like shape, comprising a pair of portions (23, 24) joined by a central portion (15) and in each of which is formed at least one through hole (3, 4) to receive a corresponding screw (5) for fixing to the bone.Advantageously, the bone plate (2) is flat with almost constant thickness and is delimited by opposite surfaces (6, 7) parallel with a single recess (8) or notch that is transversal to the longitudinal axis of bone plate (2) formed on only one (6) of said surfaces (6, 7), with the thickness (s) of the plate being less than a ninth of its maximum longitudinal extension (L).