A device for attaching a bracelet or strap to a watch case includes at least one horn integral with the watch case, and an insert integral with the end of a bracelet strand. The horn and the insert are complementary to cooperate by interlocking with each other to form a removable assembly able to make the bracelet interchangeable. The insert includes at least one stud subjected to the action of a spring, at least one stud being arranged to cooperate with at least one housing in the horn, the horn including a control member projecting radially with respect to the horn, in order to move the stud from a deployed position in which the stud holds the strand on the horn, to a retracted position in which the strand is released from the horn.