A safety cut-off for devices for producing pressurised water vapour, preferably for domestic use, characterised by comprising a hinged cover (1) which is disposed in closing/opening relationship with an access to a recess (2), preferably a funnel, through which water is poured for filling and refilling of a boiler in which the water vapour is produced, which cover (1) has a shaft (3) in relation to which there rotates a cam (4) which is integral with the cover (1), and which has an active surface which is applied to a cam surface (6) of a lever (5) which is rotatable relative to a lever shaft(7), and which, spaced from the latter, has an aperture (8) through which there slides a rod (10), which at one end incorporates a valve (9) for filling and closure, which is interposed between the recess (2) and a chamber (12) for containing water vapour as produced in the boiler, which valve (9) can adopt one of two operative positions, such that, in one position, the valve (9) acts to close a valve passage (11) which provides a communication between the recess (2) and the chamber (12), and, in the other position, the valve (9) is opened.