Abstract: An injection device includes a syringe body tubular element (9) provided with finger-pressing members (23) for holding the injection device to inject a dose of liquid, in particular medicinal liquid. The finger-pressing members consist of a flange (23), provided with an upper surface and a lower surface, including two portions with symmetrical outline (50, 51), called gripping portions, having lower support surfaces for the user's fingers, and between the support surfaces, two portions with diametrically opposed symmetrical outlines (52), called indexing portions, including in the extension of the lower surface of the flange, a lower surfaces having a convex profile formed by two slopes symmetrical relative to a longitudinal axis.