The invention relates to an infusion part (1), as well as to a simple, non-expensive inserter for said infusion part which inserter would be easy and safe for the user to handle during use and to dispose of after use. The inserter comprises a housing (26), a spring unit (19) and a sled unit (11) connected to the housing via the spring unit. The infusion part comprises a cannula (6) integrated with an insertion needle (7) and a needle protection (4) releasably secured to the infusion part and removable from the position where it protects the needle by applying a force perpendicular to the axis of the needle.