An injection apparatus is described for making an injection at a predetermined depth in skin, including: a skin positioning member for positioning on a patch of skin within an area of skin such that at least a part of the patch of skin may be held elevated above or depressed below the area of skin, an injection needle, and a guidance mechanism for guiding the injection needle to slide beneath the skin positioning member to an injection position in which the distal end of the needle lies at a predetermined distance below the skin positioning member. An injection apparatus is also described including a detachable marker unit and a securing element for securing the marker unit at an injection site prior to the making of an injection to mark the position of the injection site.