An evaporator device for active substances is designed for using active substances established in a paper tablet or the like, or in a tray with a semipermeable membrane, in gel form, comprising a base body with a U-shaped profile inside coupled by insertion to a support provided with two housings and, the former adapted in size and shape to receive within it a tray and the second to receive a tablet, so that both the tray and tablet can be placed in the same support opposite the heating surface of the device. This allows using the device equally with either format of the active substance. The device also includes a safety mechanism comprising teeth that lock in the closed position, preventing or making it difficult for children to displace or extract the support from the casing, that requires pressing inwards on two lateral opposing areas of the casing to open.