Watch intended to be mounted on a removable support

A watch intended to be removably mounted on a support, comprising a watch case and an independent removable attachment device arranged to retain the watch case in an opening provided in the support, the watch case comprising an upper portion, on the dial side, and a lower portion comprising a back cover, said lower portion being arranged to be housed inside the opening in the support and being of smaller dimensions than those of the upper portion to form a flat peripheral shoulder, wherein the attachment device comprises a flange having a central opening arranged for receiving the lower portion of the watch case and an inner rim delimiting said central opening, said inner rim being arranged to be housed inside the opening in the support, and wherein the inner rim comprises, on the inner wall thereof, a locking device for locking the attachment device on the lower portion of the watch case, arranged to allow the attachment device to be locked on the watch case in order to retain the support between the flange and the flat shoulder of the watch case and to allow the attachment device to be unlocked from the watch case by applying on the flange an outwardly directed force substantially perpendicular to the flange in order to release the support.