A quick connection that allows fastening a tool to the lifter arm of an operating machine and includes first and second joining devices associated respectively to the lifter arm and the tool aimed at being reciprocally engaged. The first joining device includes a swivel head that swivels between a raised position and a lowered one and a first gudgeon the second joining device includes a shaped body that defines a calibrated inlet opening and support structure. The swivel head, in raised position, enters the shaped body through the opening, then it rotates to its lowered position, thus bringing the first gudgeon in engagement with the support structure. The shaped body includes a stop aimed at striking a winglet of the swivel head and at preventing the swivel head from going out in any succession of movements which are not inversely equal to those carried out for the introduction.