A device for detecting the presence of a food container such as a saucepan dish or the like, placed on a heating element of a glass ceramic cooking hob comprising electrical conductor rings fed with signals which are identical but of opposite phase, between the conductor rings there being interposed a detector ring traversed by electrical signals, the conductor and detector rings being positioned in correspondence with that cooking region of the glass ceramic hob where the heating element is positioned, the signals from the detector ring varying on the basis of the presence or absence of the food container on the hob, a control being provided to measure the variation in the electrical signals and to intervene in the operation of the heating element.