Abstract: A device for the production of steam for installing on the roof of a new or existing shower standard box, so as to transform a standard shower box into a sauna. The device has a compact box-shaped roof having a fan for forced air circulation and an instantaneous vaporizer supplied directly by the water source by means o a solenoid valve operated intermittently by a timer interlocked by two thermostats. The box-shaped roof is used together with a covering screen for closing the part of the box top which is not covered by the box-shaped roof itself.