A portable electronic device, for example an electronic card, includes at least one electronic unit associated to an optical switch which can be actuated by a user and which includes two photo-detectors arranged sufficiently far from each other in the electronic device to enable the user to cover only one of the two photo-detectors with one finger. The switch includes a logical circuit to which are provided a first and a second light reception signal respectively coming from the two photo-detectors. The logical circuit is arranged to supply a signal which only indicates actuation of the optical switch when the first and second light reception signals correspond to two different logical states for the logic circuit.