A means for releasable connection between a line and the free end of a bar or rod or pin shaped element (4), e.g. the leg of a fish hook, which means comprises a sleeve shaped element (1) adapted to be attached to the line and to axially receive the free end of the bar or rod or pin shaped element (4) under cooporation between the said free end and a substantially U-shaped leaf spring (9) disposed in a cavity (5) in the sleeve shaped element (1), the free ends of the spring being bent outwardly to cooperate with oblique end faces (7) in the cavity (5) and being provided with a cut out (11) for engagement with an annular surface (16) on the bar or rod or pin shaped element (4). To prevent the spring (9) from being unintentionally opened, the side walls (8) of the cavity (5) are provided with projections (17) intended to engage with the branches of the U-shaped spring (9).