The invention relates to an inserter device for subcutaneously inserting a medical device, the inserter device comprising an outer part comprising one or more locking elements including a first locking element and one or more release elements including a first release element; a housing; and a functional part accommodated in the housing; wherein the housing comprises a sidewall with an inner surface forming a cavity, the housing extending from a first end to a second end along a first axis and comprising one or more housing guide members including a first housing guide member for engagement with one or more guide members of the functional part, and where the housing is at least partly covered by the outer part;wherein the functional part comprises a first part with a first body extending from a first end to a second end along the first axis, the first part comprising one or more first locking members; a second part releasably connected to the first part and comprising a second body extending from a first end to a second end along the first axis, the second part comprising a second guide member and one or more second locking members; an insertion needle attached to the second part; an insertion spring adapted for moving the first part from a first position to a second position in an insertion direction along the first axis in relation to the housing; and a retraction spring adapted for moving the second part from the second position to a third position in an extraction direction along the first axis in relation to the housing.