Abstract: The invention describes a device for preparing infüsions, suitable for preparing infüsions in a micro wave. The device comprises: a lowertank transparent to electromagnetic radiation, with a valve; an upper tank screwed to the lower tank; a funnel that connects the tanks; an extraction área containing material to be extracted with filtering means; a cover; and means for making the device leak tight, the device comprising áreas for shielding against electromagnetic waves in the extraction área, the upper tank and the cover. In the preferred embodiments, the device comprises a float, needles and thermal reinforcement áreas. The device allows infüsions to be obtained without the volatile compounds degrading.