A safety device (1) for a fluid transmission has a diaphragm (4) which is arranged deflectably in a feed passage (8) and which has at least one through opening (2) for the fluid. A return passage (10) for the fluid from the chamber of the consumer (9) is of such a configuration and arrangement that it can be opened and closed by deflection of the diaphragm (4), wherein the diaphragm (4) is of such a configuration that, when the fluid flow in the feed passage (8) falls below a given value, the return passage (10) is opened. The pressure in a pressure chamber (9) of a consumer can be let off by the device (1) when a pump (7) is no longer conveying.