Abstract: Device which can be fitted to a faucet in order to trigger the automatic issuance of water.Said device is integrally joined to the operating unit of said faucet and consists of a cylindrical body (3) housing a detection cell (5), said cylindrical body being placed in a cavity (41) in said operating unit and being integrally joined to the control unit (6) of said faucet, with said faucet including a window (61) positioned facing said cylindrical body (3) for the passage of the rays (62) which are necessary for the operation of said detection cell (5).