The invention relates to a needle storage magazine for storing a number of injection needles and attaching and/or detaching them to or from an injection device, the needle storage magazine comprising a crescent shaped track having a convex part and a concave part, wherein the track is adapted to hold a set of needles in respective needle supports within the track, wherein the convex part is adapted to hold unused needles and used needles, wherein a centre position (B) is defined within the concave part for a needle in use or to be used, wherein a sliding carriage is arranged for attaching the injection device to the needle storage magazine such that the centre position (B) is essentially concentric to a longitudinal axis of the injection device, wherein a separation wheel is rotatably arranged, the separation wheel having at least one notch for entraining the needle support of one unused needle at a time from the convex part into the centre position (B) or the needle support of the needle in use out of the centre position (B) onto the convex part.
